diff --git a/tools/api-checker/build.xml b/tools/api-checker/build.xml
index 9251196..9e2691d 100755
--- a/tools/api-checker/build.xml
+++ b/tools/api-checker/build.xml
@@ -42,6 +42,35 @@
 		</gwt.jar>
 	</target>
 
+	<target name="test" depends="build, compile.tests" description="Run unit tests for this project.">
+		<taskdef name="junit" classname="org.apache.tools.ant.taskdefs.optional.junit.JUnitTask">
+			<classpath>
+				<pathelement location="${gwt.tools.lib}/junit/junit-3.8.1.jar" />
+				<pathelement location="${gwt.tools.antlib}/ant-junit-1.6.5.jar" />
+			</classpath>
+		</taskdef>
+	
+		<echo message="Writing test results to ${junit.out}/reports" />
+		<mkdir dir="${junit.out}/reports" />
+	
+		<junit dir="${junit.out}" fork="yes" printsummary="yes" haltonfailure="true">
+			<classpath>
+				<pathelement location="test" />
+				<pathelement location="${gwt.build.out}/dev/core/bin"/>
+				<pathelement location="${gwt.build.out}/tools/api-checker/bin"/>
+				<pathelement location="${gwt.tools.lib}/eclipse/jdt-3.3.1.jar"/>
+				<pathelement location="${gwt.tools.lib}/junit/junit-3.8.1.jar" />
+				<pathelement location="${javac.junit.out}" />
+			</classpath>
+	
+			<formatter type="plain" />
+			<formatter type="xml" />
+			<batchtest todir="${junit.out}/reports">
+                          <fileset dir="${javac.junit.out}"
+                            includes="**/*Test.class"/> 
+			</batchtest>
+		</junit>
+	</target>
 
 	<target name="checkstyle" description="Static analysis of source">
 		<gwt.checkstyle>
diff --git a/tools/api-checker/config/gwt14_15userApi.conf b/tools/api-checker/config/gwt14_15userApi.conf
index 679a413..632afdc 100644
--- a/tools/api-checker/config/gwt14_15userApi.conf
+++ b/tools/api-checker/config/gwt14_15userApi.conf
@@ -2,17 +2,18 @@
 
 name_old gwt1462userApi
 #sourceFiles and excludedFiles are specified as colon-separated list of files
-sourceFiles_old @OLDROOT@/dev/core/super/com/google/gwt/dev/jjs/intrinsic:@OLDROOT@/user/super/com/google/gwt/emul:@OLDROOT@/user/src/com/google/gwt/core/client:@OLDROOT@/user/src/com/google/gwt/user/client:@OLDROOT@/user/src/com/google/gwt/http/client:@OLDROOT@/user/com/google/gwt/i18n
-excludedFiles_old @OLDROOT@/user/com/google/gwt/benchmarks
+sourceFiles_old @OLDROOT@/dev/core/super:@OLDROOT@/user/super:@OLDROOT@/user/src
+excludedFiles_old @OLDROOT@/user/src/com/google/gwt/junit:@OLDROOT@/user/src/com/google/gwt/i18n/rebind:@OLDROOT@/user/src/com/google/gwt/i18n/tools:@OLDROOT@/user/src/com/google/gwt/json:@OLDROOT@/user/src/com/google/gwt/user/rebind:@OLDROOT@/user/src/com/google/gwt/user/server:@OLDROOT@/user/src/com/google/gwt/user/tools:@OLDROOT@/user/super/com/google/gwt/junit
 
 ##############################################
 #new Api
 
 name_new gwt15userApi
 #sourceFiles and excludedFiles are specified as colon-separated list of files
-#works with GWT 1.5 Milestone 2, revision 2415
-sourceFiles_new ./dev/core/super/com/google/gwt/dev/jjs/intrinsic:./user/super/com/google/gwt/emul:./user/src/com/google/gwt/core/client:./user/src/com/google/gwt/user/client:./user/src/com/google/gwt/http/client:./user/src/com/google/gwt/dom:./user/src/com/google/gwt/i18n
-excludedFiles_new ./user/src/com/google/gwt/benchmarks:./user/src/com/google/gwt/i18n/rebind:./user/src/com/google/gwt/i18n/tools
+#works with GWT 1.5, revision 2859
+sourceFiles_new ./dev/core/super:./user/super:./user/src
+#:dev/core/src
+excludedFiles_new ./user/src/com/google/gwt/benchmarks:./user/src/com/google/gwt/junit:./user/src/com/google/gwt/i18n/rebind:./user/src/com/google/gwt/i18n/tools:./user/src/com/google/gwt/json:./user/src/com/google/gwt/user/rebind:./user/src/com/google/gwt/user/server:./user/src/com/google/gwt/user/tools:./user/super/com/google/gwt/benchmarks:./user/super/com/google/gwt/junit
 
 
 ##############################################
@@ -20,243 +21,174 @@
 # when adding to the white-list, include comments as to why the addition is
 # being made. This needs to be done for this initial white-list below
 
-  package com.google.gwt.core.client
-    class com.google.gwt.core.client.JavaScriptObject
-      com.google.gwt.core.client.JavaScriptObject::hostedModeReference MISSING
-      com.google.gwt.core.client.JavaScriptObject::equals(Ljava/lang/Object;) FINAL_ADDED
-      com.google.gwt.core.client.JavaScriptObject::hashCode() FINAL_ADDED
-      com.google.gwt.core.client.JavaScriptObject::toString() FINAL_ADDED
-  package com.google.gwt.lang
-    class com.google.gwt.lang.Array
-      com.google.gwt.lang.Array::Array(IIILjava/lang/String;) MISSING
-      com.google.gwt.lang.Array::clonify([Ljava/lang/Object;I) MISSING
-      com.google.gwt.lang.Array::initDims(Ljava/lang/String;Ljava/lang/Object;Ljava/lang/Object;Ljava/lang/Object;Ljava/lang/Object;) MISSING
-      com.google.gwt.lang.Array::initValues(Ljava/lang/String;IILjava/lang/Object;) MISSING
-  package com.google.gwt.user.client
-    class com.google.gwt.user.client.Element
-      com.google.gwt.user.client.Element::equals(Ljava/lang/Object;) FINAL_ADDED
-      com.google.gwt.user.client.Element::hashCode() FINAL_ADDED
-      com.google.gwt.user.client.Element::toString() FINAL_ADDED
-    class com.google.gwt.user.client.Event
-      com.google.gwt.user.client.Event::equals(Ljava/lang/Object;) FINAL_ADDED
-      com.google.gwt.user.client.Event::hashCode() FINAL_ADDED
-      com.google.gwt.user.client.Event::toString() FINAL_ADDED
-  package com.google.gwt.user.client.impl
-    class com.google.gwt.user.client.impl.DOMImplMozillaOld
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::appendChild(Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::compare(Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::createElement(Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::createInputElement(Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::createInputRadioElement(Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::createSelectElement(Z) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::getAbsoluteLeft(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::getAbsoluteTop(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::getElementAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::getElementById(Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::getElementProperty(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::getElementPropertyBoolean(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::getElementPropertyInt(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::getFirstChild(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::getImgSrc(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::getInnerHTML(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::getInnerText(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::getIntStyleAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::getNextSibling(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::getParent(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::getStyleAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::iframeGetSrc(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::init() MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::initMozilla() MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::insertBefore(Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::insertListItem(Lcom/google/gwt/user/client/Element;Ljava/lang/String;Ljava/lang/String;I) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::isOrHasChild(Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::removeChild(Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::removeElementAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::scrollIntoView(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::setElementAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::setElementProperty(Lcom/google/gwt/user/client/Element;Ljava/lang/String;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::setElementPropertyBoolean(Lcom/google/gwt/user/client/Element;Ljava/lang/String;Z) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::setElementPropertyInt(Lcom/google/gwt/user/client/Element;Ljava/lang/String;I) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::setImgSrc(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::setInnerHTML(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::setInnerText(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::setIntStyleAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;I) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::setOptionText(Lcom/google/gwt/user/client/Element;Ljava/lang/String;I) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::setStyleAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::toString(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::windowGetClientHeight() MISSING
-      com.google.gwt.user.client.impl.DOMImplMozillaOld::windowGetClientWidth() MISSING
-    class com.google.gwt.user.client.impl.DOMImplOpera
-      com.google.gwt.user.client.impl.DOMImplOpera::appendChild(Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::compare(Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::createElement(Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::createInputElement(Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::createInputRadioElement(Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::createSelectElement(Z) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::getAbsoluteLeft(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::getAbsoluteTop(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::getElementAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::getElementById(Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::getElementProperty(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::getElementPropertyBoolean(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::getElementPropertyInt(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::getFirstChild(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::getImgSrc(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::getInnerHTML(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::getInnerText(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::getIntStyleAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::getNextSibling(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::getParent(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::getStyleAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::iframeGetSrc(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::init() MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::insertBefore(Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::insertListItem(Lcom/google/gwt/user/client/Element;Ljava/lang/String;Ljava/lang/String;I) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::isOrHasChild(Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::removeChild(Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::removeElementAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::scrollIntoView(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::setElementAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::setElementProperty(Lcom/google/gwt/user/client/Element;Ljava/lang/String;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::setElementPropertyBoolean(Lcom/google/gwt/user/client/Element;Ljava/lang/String;Z) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::setElementPropertyInt(Lcom/google/gwt/user/client/Element;Ljava/lang/String;I) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::setImgSrc(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::setInnerHTML(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::setInnerText(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::setIntStyleAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;I) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::setOptionText(Lcom/google/gwt/user/client/Element;Ljava/lang/String;I) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::setStyleAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;Ljava/lang/String;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::toString(Lcom/google/gwt/user/client/Element;) MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::windowGetClientHeight() MISSING
-      com.google.gwt.user.client.impl.DOMImplOpera::windowGetClientWidth() MISSING
-  package com.google.gwt.user.client.rpc.core.java.lang
-    com.google.gwt.user.client.rpc.core.java.lang.boolean_Array_CustomFieldSerializer MISSING
-    com.google.gwt.user.client.rpc.core.java.lang.byte_Array_CustomFieldSerializer MISSING
-    com.google.gwt.user.client.rpc.core.java.lang.char_Array_CustomFieldSerializer MISSING
-    com.google.gwt.user.client.rpc.core.java.lang.double_Array_CustomFieldSerializer MISSING
-    com.google.gwt.user.client.rpc.core.java.lang.float_Array_CustomFieldSerializer MISSING
-    com.google.gwt.user.client.rpc.core.java.lang.int_Array_CustomFieldSerializer MISSING
-    com.google.gwt.user.client.rpc.core.java.lang.long_Array_CustomFieldSerializer MISSING
-    com.google.gwt.user.client.rpc.core.java.lang.short_Array_CustomFieldSerializer MISSING
-  package com.google.gwt.user.client.ui
-    class com.google.gwt.user.client.ui.Button
-      com.google.gwt.user.client.ui.Button::setElement(Lcom/google/gwt/user/client/Element;) FINAL_ADDED
-      com.google.gwt.user.client.ui.Button::setElement(Lcom/google/gwt/user/client/Element;) OVERLOADED_METHOD_CALL Many methods in the new API with similar signatures. Methods = [protected void setElement(com.google.gwt.user.client.Element elem), protected final void setElement(com.google.gwt.dom.client.Element elem)] This might break API source compatibility
-    class com.google.gwt.user.client.ui.ChangeListenerCollection
-      com.google.gwt.user.client.ui.ChangeListenerCollection::add(ILjava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.ChangeListenerCollection::add(Ljava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.ChangeListenerCollection::set(ILjava/lang/Object;) MISSING
-    class com.google.gwt.user.client.ui.CheckBox
-      com.google.gwt.user.client.ui.CheckBox::setElement(Lcom/google/gwt/user/client/Element;) FINAL_ADDED
-      com.google.gwt.user.client.ui.CheckBox::setElement(Lcom/google/gwt/user/client/Element;) OVERLOADED_METHOD_CALL Many methods in the new API with similar signatures. Methods = [protected void setElement(com.google.gwt.user.client.Element elem), protected final void setElement(com.google.gwt.dom.client.Element elem)] This might break API source compatibility
-    class com.google.gwt.user.client.ui.ClickListenerCollection
-      com.google.gwt.user.client.ui.ClickListenerCollection::add(ILjava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.ClickListenerCollection::add(Ljava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.ClickListenerCollection::set(ILjava/lang/Object;) MISSING
-    class com.google.gwt.user.client.ui.FocusListenerCollection
-      com.google.gwt.user.client.ui.FocusListenerCollection::add(ILjava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.FocusListenerCollection::add(Ljava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.FocusListenerCollection::set(ILjava/lang/Object;) MISSING
-    class com.google.gwt.user.client.ui.FormHandlerCollection
-      com.google.gwt.user.client.ui.FormHandlerCollection::add(ILjava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.FormHandlerCollection::add(Ljava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.FormHandlerCollection::set(ILjava/lang/Object;) MISSING
-    class com.google.gwt.user.client.ui.KeyboardListenerCollection
-      com.google.gwt.user.client.ui.KeyboardListenerCollection::add(ILjava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.KeyboardListenerCollection::add(Ljava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.KeyboardListenerCollection::set(ILjava/lang/Object;) MISSING
-    class com.google.gwt.user.client.ui.ListBox
-      com.google.gwt.user.client.ui.ListBox::setElement(Lcom/google/gwt/user/client/Element;) OVERLOADED_METHOD_CALL Many methods in the new API with similar signatures. Methods = [protected final void setElement(com.google.gwt.dom.client.Element elem), protected void setElement(com.google.gwt.user.client.Element elem)] This might break API source compatibility
-      com.google.gwt.user.client.ui.ListBox::setElement(Lcom/google/gwt/user/client/Element;) FINAL_ADDED
-    class com.google.gwt.user.client.ui.LoadListenerCollection
-      com.google.gwt.user.client.ui.LoadListenerCollection::add(ILjava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.LoadListenerCollection::add(Ljava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.LoadListenerCollection::set(ILjava/lang/Object;) MISSING
-    class com.google.gwt.user.client.ui.MenuItem
-      com.google.gwt.user.client.ui.MenuItem::setElement(Lcom/google/gwt/user/client/Element;) FINAL_ADDED
-      com.google.gwt.user.client.ui.MenuItem::setElement(Lcom/google/gwt/user/client/Element;) OVERLOADED_METHOD_CALL Many methods in the new API with similar signatures. Methods = [protected final void setElement(com.google.gwt.dom.client.Element elem), protected void setElement(com.google.gwt.user.client.Element elem)] This might break API source compatibility
-    class com.google.gwt.user.client.ui.MouseListenerCollection
-      com.google.gwt.user.client.ui.MouseListenerCollection::add(ILjava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.MouseListenerCollection::add(Ljava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.MouseListenerCollection::set(ILjava/lang/Object;) MISSING
-    class com.google.gwt.user.client.ui.MouseWheelListenerCollection
-      com.google.gwt.user.client.ui.MouseWheelListenerCollection::add(ILjava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.MouseWheelListenerCollection::add(Ljava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.MouseWheelListenerCollection::set(ILjava/lang/Object;) MISSING
-    class com.google.gwt.user.client.ui.PopupListenerCollection
-      com.google.gwt.user.client.ui.PopupListenerCollection::add(ILjava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.PopupListenerCollection::add(Ljava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.PopupListenerCollection::set(ILjava/lang/Object;) MISSING
-    class com.google.gwt.user.client.ui.PushButton
-      com.google.gwt.user.client.ui.PushButton::setElement(Lcom/google/gwt/user/client/Element;) OVERLOADED_METHOD_CALL Many methods in the new API with similar signatures. Methods = [protected final void setElement(com.google.gwt.dom.client.Element elem), protected void setElement(com.google.gwt.user.client.Element elem)] This might break API source compatibility
-      com.google.gwt.user.client.ui.PushButton::setElement(Lcom/google/gwt/user/client/Element;) FINAL_ADDED
-    class com.google.gwt.user.client.ui.RichTextArea
-      com.google.gwt.user.client.ui.RichTextArea::setElement(Lcom/google/gwt/user/client/Element;) OVERLOADED_METHOD_CALL Many methods in the new API with similar signatures. Methods = [protected final void setElement(com.google.gwt.dom.client.Element elem), protected void setElement(com.google.gwt.user.client.Element elem)] This might break API source compatibility
-      com.google.gwt.user.client.ui.RichTextArea::setElement(Lcom/google/gwt/user/client/Element;) FINAL_ADDED
-    class com.google.gwt.user.client.ui.ScrollListenerCollection
-      com.google.gwt.user.client.ui.ScrollListenerCollection::add(ILjava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.ScrollListenerCollection::add(Ljava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.ScrollListenerCollection::set(ILjava/lang/Object;) MISSING
-    class com.google.gwt.user.client.ui.TabListenerCollection
-      com.google.gwt.user.client.ui.TabListenerCollection::add(ILjava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.TabListenerCollection::add(Ljava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.TabListenerCollection::set(ILjava/lang/Object;) MISSING
-    class com.google.gwt.user.client.ui.TableListenerCollection
-      com.google.gwt.user.client.ui.TableListenerCollection::add(ILjava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.TableListenerCollection::add(Ljava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.TableListenerCollection::set(ILjava/lang/Object;) MISSING
-    class com.google.gwt.user.client.ui.TextBoxBase
-      com.google.gwt.user.client.ui.TextBoxBase::setElement(Lcom/google/gwt/user/client/Element;) OVERLOADED_METHOD_CALL Many methods in the new API with similar signatures. Methods = [protected void setElement(com.google.gwt.user.client.Element elem), protected final void setElement(com.google.gwt.dom.client.Element elem)] This might break API source compatibility
-      com.google.gwt.user.client.ui.TextBoxBase::setElement(Lcom/google/gwt/user/client/Element;) FINAL_ADDED
-    class com.google.gwt.user.client.ui.ToggleButton
-      com.google.gwt.user.client.ui.ToggleButton::setElement(Lcom/google/gwt/user/client/Element;) OVERLOADED_METHOD_CALL Many methods in the new API with similar signatures. Methods = [protected void setElement(com.google.gwt.user.client.Element elem), protected final void setElement(com.google.gwt.dom.client.Element elem)] This might break API source compatibility
-      com.google.gwt.user.client.ui.ToggleButton::setElement(Lcom/google/gwt/user/client/Element;) FINAL_ADDED
-    class com.google.gwt.user.client.ui.TreeItem
-      com.google.gwt.user.client.ui.TreeItem::setElement(Lcom/google/gwt/user/client/Element;) FINAL_ADDED
-      com.google.gwt.user.client.ui.TreeItem::setElement(Lcom/google/gwt/user/client/Element;) OVERLOADED_METHOD_CALL Many methods in the new API with similar signatures. Methods = [protected final void setElement(com.google.gwt.dom.client.Element elem), protected void setElement(com.google.gwt.user.client.Element elem)] This might break API source compatibility
-    class com.google.gwt.user.client.ui.TreeListenerCollection
-      com.google.gwt.user.client.ui.TreeListenerCollection::add(ILjava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.TreeListenerCollection::add(Ljava/lang/Object;) MISSING
-      com.google.gwt.user.client.ui.TreeListenerCollection::set(ILjava/lang/Object;) MISSING
-    class com.google.gwt.user.client.ui.Widget
-      com.google.gwt.user.client.ui.Widget::setElement(Lcom/google/gwt/user/client/Element;) FINAL_ADDED
-      com.google.gwt.user.client.ui.Widget::setElement(Lcom/google/gwt/user/client/Element;) OVERLOADED_METHOD_CALL Many methods in the new API with similar signatures. Methods = [protected final void setElement(com.google.gwt.dom.client.Element elem), protected void setElement(com.google.gwt.user.client.Element elem)] This might break API source compatibility
-  package java.lang
-    class java.lang.Byte
-      java.lang.Byte::compareTo(Ljava/lang/Object;) MISSING
-    class java.lang.Character
-      java.lang.Character::compareTo(Ljava/lang/Object;) MISSING
-    java.lang.Class FINAL_ADDED
-    class java.lang.Double
-      java.lang.Double::compareTo(Ljava/lang/Object;) MISSING
-    class java.lang.Float
-      java.lang.Float::compareTo(Ljava/lang/Object;) MISSING
-    class java.lang.Integer
-      java.lang.Integer::compareTo(Ljava/lang/Object;) MISSING
-    class java.lang.Long
-      java.lang.Long::compareTo(Ljava/lang/Object;) MISSING
-    class java.lang.Number
-      java.lang.Number::__hexDigits MISSING
-      java.lang.Number::__decodeAndValidateLong(Ljava/lang/String;JJ) MISSING
-      java.lang.Number::__parseAndValidateLong(Ljava/lang/String;IJJ) MISSING
-    class java.lang.Object
-      java.lang.Object::typeName MISSING
-    class java.lang.Short
-      java.lang.Short::compareTo(Ljava/lang/Object;) MISSING
-    class java.lang.String
-      java.lang.String::String([CII) OVERLOADED_METHOD_CALL Many methods in the new API with similar signatures. Methods = [public String(char[] value, int offset, int count), public String(int[] codePoints, int offset, int count)] This might break API source compatibility
-      java.lang.String::compareTo(Ljava/lang/Object;) MISSING
-    class java.lang.StringBuffer
-      java.lang.StringBuffer::append([CII) OVERLOADED_METHOD_CALL Many methods in the new API with similar signatures. Methods = [public java.lang.StringBuffer append(char[] x, int start, int len), public java.lang.StringBuffer append(java.lang.CharSequence x, int start, int end)] This might break API source compatibility
-      java.lang.StringBuffer::insert(I[CII) OVERLOADED_METHOD_CALL Many methods in the new API with similar signatures. Methods = [public java.lang.StringBuffer insert(int index, char[] x, int offset, int len), public java.lang.StringBuffer insert(int index, java.lang.CharSequence chars, int start, int end)] This might break API source compatibility
-  package java.util
-    class java.util.ArrayList
-      java.util.ArrayList::indexOutOfBounds(I) MISSING
-    class java.util.Arrays
-      java.util.Arrays::sort([Ljava/lang/Object;) OVERLOADED_METHOD_CALL Many methods in the new API with similar signatures. Methods = [public static void sort(float[] array), public static void sort(short[] array), public static void sort(double[] array), public static void sort(java.lang.Object[] array), public static void sort(byte[] array), public static void sort(long[] array), public static void sort(int[] array)] This might break API source compatibility
-    class java.util.Date
-      java.util.Date::__parse(Ljava/lang/String;) MISSING
-      java.util.Date::compareTo(Ljava/lang/Object;) MISSING
-    class java.util.Vector
-      java.util.Vector::indexOutOfBounds(I) MISSING
-
+com.google.gwt.core.client.JavaScriptObject::equals(Ljava/lang/Object;) FINAL_ADDED
+com.google.gwt.core.client.JavaScriptObject::hashCode() FINAL_ADDED
+com.google.gwt.core.client.JavaScriptObject::hostedModeReference MISSING
+com.google.gwt.core.client.JavaScriptObject::toString() FINAL_ADDED
+com.google.gwt.i18n.client.DateTimeFormat::parse(Ljava/lang/String;) EXCEPTION_TYPE_ERROR
+com.google.gwt.i18n.client.NumberFormat::NumberFormat(Lcom/google/gwt/i18n/client/constants/NumberConstants;Lcom/google/gwt/i18n/client/constants/CurrencyCodeMapConstants;Ljava/lang/String;Ljava/lang/String;) MISSING
+com.google.gwt.i18n.client.NumberFormat::NumberFormat(Ljava/lang/String;Ljava/lang/String;) MISSING
+com.google.gwt.i18n.client.NumberFormat::parse(Ljava/lang/String;) EXCEPTION_TYPE_ERROR
+com.google.gwt.i18n.client.NumberFormat::parse(Ljava/lang/String;[I) EXCEPTION_TYPE_ERROR
+com.google.gwt.i18n.client.impl.ConstantMap::put(Ljava/lang/Object;Ljava/lang/Object;) MISSING
+com.google.gwt.lang.Array::Array(IIILjava/lang/String;) MISSING
+com.google.gwt.lang.Array::clonify([Ljava/lang/Object;I) MISSING
+com.google.gwt.lang.Array::initDims(Ljava/lang/String;Ljava/lang/Object;Ljava/lang/Object;Ljava/lang/Object;Ljava/lang/Object;) MISSING
+com.google.gwt.lang.Array::initValues(Ljava/lang/String;IILjava/lang/Object;) MISSING
+com.google.gwt.user.client.Element::equals(Ljava/lang/Object;) FINAL_ADDED
+com.google.gwt.user.client.Element::hashCode() FINAL_ADDED
+com.google.gwt.user.client.Element::toString() FINAL_ADDED
+com.google.gwt.user.client.Event::equals(Ljava/lang/Object;) FINAL_ADDED
+com.google.gwt.user.client.Event::hashCode() FINAL_ADDED
+com.google.gwt.user.client.Event::toString() FINAL_ADDED
+com.google.gwt.user.client.impl.DOMImpl::appendChild(Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::compare(Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::createElement(Ljava/lang/String;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::createInputElement(Ljava/lang/String;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::createInputRadioElement(Ljava/lang/String;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::createSelectElement(Z) MISSING
+com.google.gwt.user.client.impl.DOMImpl::getAbsoluteLeft(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::getAbsoluteTop(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::getElementAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::getElementById(Ljava/lang/String;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::getElementProperty(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::getElementPropertyBoolean(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::getElementPropertyInt(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::getFirstChild(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::getImgSrc(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::getInnerHTML(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::getInnerText(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::getIntStyleAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::getNextSibling(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::getParent(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::getStyleAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::init() MISSING
+com.google.gwt.user.client.impl.DOMImpl::insertBefore(Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::insertListItem(Lcom/google/gwt/user/client/Element;Ljava/lang/String;Ljava/lang/String;I) MISSING
+com.google.gwt.user.client.impl.DOMImpl::isOrHasChild(Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::removeChild(Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::removeElementAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::scrollIntoView(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::setElementAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;Ljava/lang/String;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::setElementProperty(Lcom/google/gwt/user/client/Element;Ljava/lang/String;Ljava/lang/String;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::setElementPropertyBoolean(Lcom/google/gwt/user/client/Element;Ljava/lang/String;Z) MISSING
+com.google.gwt.user.client.impl.DOMImpl::setElementPropertyInt(Lcom/google/gwt/user/client/Element;Ljava/lang/String;I) MISSING
+com.google.gwt.user.client.impl.DOMImpl::setImgSrc(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::setInnerHTML(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::setInnerText(Lcom/google/gwt/user/client/Element;Ljava/lang/String;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::setIntStyleAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;I) MISSING
+com.google.gwt.user.client.impl.DOMImpl::setOptionText(Lcom/google/gwt/user/client/Element;Ljava/lang/String;I) MISSING
+com.google.gwt.user.client.impl.DOMImpl::setStyleAttribute(Lcom/google/gwt/user/client/Element;Ljava/lang/String;Ljava/lang/String;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::toString(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImpl::windowGetClientHeight() MISSING
+com.google.gwt.user.client.impl.DOMImpl::windowGetClientWidth() MISSING
+com.google.gwt.user.client.impl.DOMImplMozillaOld::compare(Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImplMozillaOld::createInputRadioElement(Ljava/lang/String;) MISSING
+com.google.gwt.user.client.impl.DOMImplMozillaOld::getAbsoluteLeft(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImplMozillaOld::getAbsoluteTop(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImplMozillaOld::getFirstChild(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImplMozillaOld::getNextSibling(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImplMozillaOld::getParent(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImplMozillaOld::iframeGetSrc(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImplMozillaOld::init() MISSING
+com.google.gwt.user.client.impl.DOMImplMozillaOld::initMozilla() MISSING
+com.google.gwt.user.client.impl.DOMImplMozillaOld::isOrHasChild(Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImplMozillaOld::toString(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImplOpera::compare(Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImplOpera::createInputRadioElement(Ljava/lang/String;) MISSING
+com.google.gwt.user.client.impl.DOMImplOpera::getAbsoluteLeft(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImplOpera::getAbsoluteTop(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImplOpera::getFirstChild(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImplOpera::getNextSibling(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImplOpera::getParent(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImplOpera::iframeGetSrc(Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.impl.DOMImplOpera::init() MISSING
+com.google.gwt.user.client.impl.DOMImplOpera::isOrHasChild(Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/Element;) MISSING
+com.google.gwt.user.client.rpc.core.java.lang.boolean_Array_CustomFieldSerializer MISSING
+com.google.gwt.user.client.rpc.core.java.lang.byte_Array_CustomFieldSerializer MISSING
+com.google.gwt.user.client.rpc.core.java.lang.char_Array_CustomFieldSerializer MISSING
+com.google.gwt.user.client.rpc.core.java.lang.double_Array_CustomFieldSerializer MISSING
+com.google.gwt.user.client.rpc.core.java.lang.float_Array_CustomFieldSerializer MISSING
+com.google.gwt.user.client.rpc.core.java.lang.int_Array_CustomFieldSerializer MISSING
+com.google.gwt.user.client.rpc.core.java.lang.long_Array_CustomFieldSerializer MISSING
+com.google.gwt.user.client.rpc.core.java.lang.short_Array_CustomFieldSerializer MISSING
+com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamReader::rememberDecodedObject(Ljava/lang/Object;) MISSING
+com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter::writeLong(J) ABSTRACT_ADDED
+com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter::writeLong(J) EXCEPTION_TYPE_ERROR
+com.google.gwt.user.client.ui.ChangeListenerCollection::add(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.ChangeListenerCollection::add(Ljava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.ChangeListenerCollection::set(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.ClickListenerCollection::add(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.ClickListenerCollection::add(Ljava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.ClickListenerCollection::set(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.FocusListenerCollection::add(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.FocusListenerCollection::add(Ljava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.FocusListenerCollection::set(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.FocusWidget::setElement(Lcom/google/gwt/user/client/Element;) FINAL_ADDED
+com.google.gwt.user.client.ui.FocusWidget::setElement(Lcom/google/gwt/user/client/Element;) OVERLOADED_METHOD_CALL
+com.google.gwt.user.client.ui.FormHandlerCollection::add(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.FormHandlerCollection::add(Ljava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.FormHandlerCollection::fireOnComplete(Ljava/lang/Object;Ljava/lang/String;) MISSING
+com.google.gwt.user.client.ui.FormHandlerCollection::fireOnSubmit(Ljava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.FormHandlerCollection::set(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.FormSubmitCompleteEvent::FormSubmitCompleteEvent(Ljava/lang/Object;Ljava/lang/String;) MISSING
+com.google.gwt.user.client.ui.FormSubmitEvent::FormSubmitEvent(Ljava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.KeyboardListenerCollection::add(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.KeyboardListenerCollection::add(Ljava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.KeyboardListenerCollection::set(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.LoadListenerCollection::add(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.LoadListenerCollection::add(Ljava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.LoadListenerCollection::set(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.MouseListenerCollection::add(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.MouseListenerCollection::add(Ljava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.MouseListenerCollection::set(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.MouseWheelListenerCollection::add(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.MouseWheelListenerCollection::add(Ljava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.MouseWheelListenerCollection::set(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.PopupListenerCollection::add(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.PopupListenerCollection::add(Ljava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.PopupListenerCollection::set(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.ScrollListenerCollection::add(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.ScrollListenerCollection::add(Ljava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.ScrollListenerCollection::set(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.TabListenerCollection::add(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.TabListenerCollection::add(Ljava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.TabListenerCollection::set(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.TableListenerCollection::add(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.TableListenerCollection::add(Ljava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.TableListenerCollection::set(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.TreeListenerCollection::add(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.TreeListenerCollection::add(Ljava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.TreeListenerCollection::set(ILjava/lang/Object;) MISSING
+com.google.gwt.user.client.ui.UIObject::setElement(Lcom/google/gwt/user/client/Element;) FINAL_ADDED
+com.google.gwt.user.client.ui.UIObject::setElement(Lcom/google/gwt/user/client/Element;) OVERLOADED_METHOD_CALL
+com.google.gwt.user.client.ui.Widget::setElement(Lcom/google/gwt/user/client/Element;) FINAL_ADDED
+com.google.gwt.user.client.ui.Widget::setElement(Lcom/google/gwt/user/client/Element;) OVERLOADED_METHOD_CALL
+java.lang.Byte::compareTo(Ljava/lang/Object;) MISSING
+java.lang.Character::compareTo(Ljava/lang/Object;) MISSING
+java.lang.Class FINAL_ADDED
+java.lang.Double::compareTo(Ljava/lang/Object;) MISSING
+java.lang.Float::compareTo(Ljava/lang/Object;) MISSING
+java.lang.IllegalArgumentException::IllegalArgumentException(Ljava/lang/String;) OVERLOADED_METHOD_CALL
+java.lang.Integer::compareTo(Ljava/lang/Object;) MISSING
+java.lang.Long::compareTo(Ljava/lang/Object;) MISSING
+java.lang.Number::__decodeAndValidateLong(Ljava/lang/String;JJ) MISSING
+java.lang.Number::__hexDigits MISSING
+java.lang.Number::__parseAndValidateLong(Ljava/lang/String;IJJ) MISSING
+java.lang.Object::typeId MISSING
+java.lang.Object::typeName MISSING
+java.lang.Short::compareTo(Ljava/lang/Object;) MISSING
+java.lang.StackTraceElement FINAL_ADDED
+java.lang.StackTraceElement::finalize() MISSING
+java.lang.String::String([CII) OVERLOADED_METHOD_CALL
+java.lang.String::compareTo(Ljava/lang/Object;) MISSING
+java.lang.StringBuffer::append([CII) OVERLOADED_METHOD_CALL
+java.lang.StringBuffer::insert(I[CII) OVERLOADED_METHOD_CALL
+java.lang.UnsupportedOperationException::UnsupportedOperationException(Ljava/lang/String;) OVERLOADED_METHOD_CALL
+java.util.AbstractList::indexOutOfBounds(I) MISSING
+java.util.ArrayList::indexOf(Ljava/lang/Object;I) MISSING
+java.util.ArrayList::lastIndexOf(Ljava/lang/Object;I) MISSING
+java.util.ArrayList::setSize(I) MISSING
+java.util.Arrays::sort([Ljava/lang/Object;) OVERLOADED_METHOD_CALL
+java.util.Date::__parse(Ljava/lang/String;) MISSING
+java.util.Date::compareTo(Ljava/lang/Object;) MISSING
diff --git a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiAbstractMethod.java b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiAbstractMethod.java
index 4d86526..7089ef5 100644
--- a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiAbstractMethod.java
+++ b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiAbstractMethod.java
@@ -16,17 +16,19 @@
 package com.google.gwt.tools.apichecker;
 
 import com.google.gwt.core.ext.typeinfo.JAbstractMethod;
+import com.google.gwt.core.ext.typeinfo.JClassType;
 import com.google.gwt.core.ext.typeinfo.JParameter;
 import com.google.gwt.core.ext.typeinfo.JType;
 
-import java.util.ArrayList;
+import java.util.List;
 
 /**
  * abstract super-class for ApiMethod and ApiConstructor.
  */
-public abstract class ApiAbstractMethod {
+abstract class ApiAbstractMethod implements Comparable<ApiAbstractMethod>,
+    ApiElement {
 
-  public static String computeApiSignature(JAbstractMethod method) {
+  static String computeApiSignature(JAbstractMethod method) {
     String className = method.getEnclosingType().getQualifiedSourceName();
     StringBuffer sb = new StringBuffer();
     sb.append(className);
@@ -35,7 +37,7 @@
     return sb.toString();
   }
 
-  public static String computeInternalSignature(JAbstractMethod method) {
+  static String computeInternalSignature(JAbstractMethod method) {
     StringBuffer sb = new StringBuffer();
     sb.append(method.getName());
     sb.append("(");
@@ -49,44 +51,66 @@
     return sb.toString();
   }
 
-  ApiClass apiClass;
-
+  final ApiClass apiClass;
   String apiSignature = null;
-
-  JAbstractMethod method;
+  final JAbstractMethod method;
+  String relativeSignature = null;
 
   public ApiAbstractMethod(JAbstractMethod method, ApiClass apiClass) {
     this.method = method;
     this.apiClass = apiClass;
   }
 
-  public String getApiSignature() {
-    if (apiSignature == null) {
-      apiSignature = computeApiSignature();
-    }
-    return apiSignature;
+  public int compareTo(ApiAbstractMethod other) {
+    return getRelativeSignature().compareTo(other.getRelativeSignature());
   }
 
-  // for a non-primitive type, someone can pass it null as a parameter
-  public String getCoarseSignature() {
-    StringBuffer returnStr = new StringBuffer();
-    JParameter[] parameters = method.getParameters();
-    for (JParameter parameter : parameters) {
-      JType type = parameter.getType();
-      if (type.isPrimitive() != null) {
-        returnStr.append(type.getJNISignature());
-      } else {
-        returnStr.append("c");
-      }
-      returnStr.append(";"); // to mark the end of a type
+  /**
+   * Used in set comparisons.
+   */
+  @Override
+  public boolean equals(Object o) {
+    if (o instanceof ApiAbstractMethod) {
+      ApiAbstractMethod other = (ApiAbstractMethod) o;
+      return getApiSignature().equals(other.getApiSignature());
     }
-    return returnStr.toString();
+    return false;
   }
 
-  public JAbstractMethod getMethodObject() {
+  public JAbstractMethod getMethod() {
     return method;
   }
 
+  public String getRelativeSignature() {
+    if (relativeSignature == null) {
+      relativeSignature = computeRelativeSignature();
+    }
+    return relativeSignature;
+  }
+
+  @Override
+  public int hashCode() {
+    return getApiSignature().hashCode();
+  }
+
+  public boolean isCompatible(ApiAbstractMethod methodInNew) {
+    JParameter[] parametersInNew = methodInNew.getMethod().getParameters();
+    int length = parametersInNew.length;
+    if (length != method.getParameters().length) {
+      return false;
+    }
+    for (int i = 0; i < length; i++) {
+      if (!ApiDiffGenerator.isFirstTypeAssignableToSecond(
+          method.getParameters()[i].getType(), parametersInNew[i].getType())) {
+        return false;
+      }
+    }
+    // Control reaches here iff methods are compatible with respect to
+    // parameters and return type. For source compatibility, I do not need to
+    // check in which classes the methods are declared.
+    return true;
+  }
+
   // Not sure the above implementation is sufficient. If need be, look at the
   // implementation below.
   // public String getCoarseSignature() {
@@ -109,27 +133,6 @@
   // return returnStr.toString();
   // }
 
-  public abstract ArrayList<ApiChange.Status> getModifierChanges(
-      ApiAbstractMethod newMethod);
-
-  public boolean isCompatible(ApiAbstractMethod methodInNew) {
-    JParameter[] parametersInNew = methodInNew.getMethodObject().getParameters();
-    int length = parametersInNew.length;
-    if (length != method.getParameters().length) {
-      return false;
-    }
-    for (int i = 0; i < length; i++) {
-      if (!ApiDiffGenerator.isFirstTypeAssignableToSecond(
-          method.getParameters()[i].getType(), parametersInNew[i].getType())) {
-        return false;
-      }
-    }
-    // Control reaches here iff methods are compatible with respect to
-    // parameters and return type. For source compatibility, I do not need to
-    // check in which classes the methods are declared.
-    return true;
-  }
-
   @Override
   public String toString() {
     return method.toString();
@@ -141,4 +144,48 @@
 
   abstract ApiChange checkReturnTypeCompatibility(ApiAbstractMethod newMethod);
 
+  String getApiSignature() {
+    if (apiSignature == null) {
+      apiSignature = computeApiSignature();
+    }
+    return apiSignature;
+  }
+
+  // for a non-primitive type, someone can pass it null as a parameter
+  String getCoarseSignature() {
+    StringBuffer returnStr = new StringBuffer();
+    JParameter[] parameters = method.getParameters();
+    for (JParameter parameter : parameters) {
+      JType type = parameter.getType();
+      if (type.isPrimitive() != null) {
+        returnStr.append(type.getJNISignature());
+      } else {
+        returnStr.append("c");
+      }
+      returnStr.append(";"); // to mark the end of a type
+    }
+    return returnStr.toString();
+  }
+
+  /**
+   * Find changes in modifiers. returns a possibly immutable list.
+   * 
+   */
+  abstract List<ApiChange.Status> getModifierChanges(ApiAbstractMethod newMethod);
+
+  private String computeRelativeSignature() {
+    String signature = computeInternalSignature(method);
+    if (ApiCompatibilityChecker.DEBUG) {
+      JClassType enclosingType = method.getEnclosingType();
+      return apiClass.getClassObject().getQualifiedSourceName()
+          + "::"
+          + signature
+          + " defined in "
+          + (enclosingType == null ? "null enclosing type "
+              : enclosingType.getQualifiedSourceName());
+    }
+    return apiClass.getClassObject().getQualifiedSourceName() + "::"
+        + signature;
+  }
+
 }
diff --git a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiChange.java b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiChange.java
index 2bdd6dc..323454f 100644
--- a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiChange.java
+++ b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiChange.java
@@ -16,6 +16,10 @@
 
 package com.google.gwt.tools.apichecker;
 
+
+import java.util.HashMap;
+import java.util.Map;
+
 /**
  * 
  * An ApiChange message.Each message is a Status followed by an optional String
@@ -23,73 +27,91 @@
  * 
  */
 
-public class ApiChange {
+final class ApiChange implements Comparable<ApiChange> {
 
   // add specific changes. For example, add FINAL_ADDED and
   // ABSTRACT_ADDED instead of API_ATTRIBUTES_CHANGED
-  static enum Status {
-    ABSTRACT_ADDED("ABSTRACT_ADDED"),
+  enum Status {
+    ABSTRACT_ADDED,
 
-    ATTRIBUTES_WARNING("ATTRIBUTES_CHANGED_WARNING"),
+    ATTRIBUTES_CHANGED_WARNING,
 
-    COMPATIBLE("COMPATIBLE"),
+    COMPATIBLE,
 
-    COMPATIBLE_WITH("COMPATIBLE_WITH"),
+    COMPATIBLE_WITH,
 
-    EXCEPTIONS_ERROR("EXCEPTION_TYPE_ERROR"),
+    EXCEPTION_TYPE_ERROR,
 
-    FINAL_ADDED("FINAL_ADDED"),
+    FINAL_ADDED,
 
-    MISSING("MISSING"),
+    MISSING,
 
-    NONABSTRACT_CLASS_MADE_INTERFACE("NONABSTRACT_CLASS_MADE_INTERFACE"),
+    NONABSTRACT_CLASS_MADE_INTERFACE,
 
-    OVERLOADED("OVERLOADED_METHOD_CALL"),
+    OVERLOADED_METHOD_CALL,
 
-    RETURN_TYPE_ERROR("RETURN_TYPE_ERROR"),
+    RETURN_TYPE_ERROR,
 
-    STATIC_ADDED("STATIC_ADDED"),
+    STATIC_ADDED,
 
-    STATIC_REMOVED("STATIC_REMOVED"),
+    STATIC_REMOVED,
 
-    SUBCLASSABLE_API_CLASS_MADE_INTERFACE("SUBCLASSABLE_CLASS_MADE_INTERFACE"),
+    SUBCLASSABLE_API_CLASS_MADE_INTERFACE,
 
-    SUBCLASSABLE_API_INTERFACE_MADE_CLASS("SUBCLASSABLE_INTERFACE_MADE_CLASS");
+    SUBCLASSABLE_API_INTERFACE_MADE_CLASS,
+  }
 
-    private final String str;
-
-    Status(String str) {
-      this.str = str;
-    }
-
-    @Override
-    public final String toString() {
-      return str;
+  private static Map<String, Status> cache = new HashMap<String, Status>();
+  static {
+    for (Status tempStatus : Status.values()) {
+      cache.put(tempStatus.name(), tempStatus);
     }
   }
 
+  public static boolean contains(String str) {
+    return cache.get(str) != null;
+  }
+
+  private ApiElement element = null;
   private String message = null;
+
   private Status status = null;
 
-  public ApiChange(Status status) {
-    this.status = status;
+  private String stringRepresentation = null;
+
+  public ApiChange(ApiElement element, Status status) {
+    this(element, status, null);
   }
 
-  public ApiChange(Status status, String message) {
+  public ApiChange(ApiElement element, Status status, String message) {
+    this.element = element;
     this.status = status;
     this.message = message;
   }
 
+  public int compareTo(ApiChange arg0) {
+    return this.toString().compareTo(arg0.toString());
+  }
+
+  public ApiElement getApiElement() {
+    return element;
+  }
+
+  public String getMessage() {
+    return message;
+  }
+
   public Status getStatus() {
     return status;
   }
- 
+
   @Override
   public String toString() {
-    if (message != null) {
-      return status + " " + message;
+    if (stringRepresentation == null) {
+      stringRepresentation =
+          element.getRelativeSignature() + ApiDiffGenerator.DELIMITER
+              + status.name();
     }
-    return status.toString();
+    return stringRepresentation;
   }
-
 }
diff --git a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiClass.java b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiClass.java
index f2a0d74..c883930 100644
--- a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiClass.java
+++ b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiClass.java
@@ -17,226 +17,160 @@
 
 import com.google.gwt.core.ext.TreeLogger;
 import com.google.gwt.core.ext.typeinfo.JAbstractMethod;
-import com.google.gwt.core.ext.typeinfo.JMethod;
 import com.google.gwt.core.ext.typeinfo.JClassType;
-import com.google.gwt.core.ext.typeinfo.JConstructor;
 import com.google.gwt.core.ext.typeinfo.JField;
+import com.google.gwt.core.ext.typeinfo.JMethod;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
+import java.util.EnumMap;
 import java.util.HashMap;
 import java.util.HashSet;
-import java.util.Iterator;
 import java.util.LinkedList;
+import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 /**
  * Encapsulates an API class.
  */
-public class ApiClass {
+final class ApiClass implements Comparable<ApiClass>, ApiElement {
   /**
    * Enum for indexing the common storage used for methods and constructors
    * 
    */
   public static enum MethodType {
-    CONSTRUCTOR(0), METHOD(1);
-
-    private final int id;
-
-    MethodType(int id) {
-      this.id = id;
-    }
-
-    public int getId() {
-      return id;
-    }
+    CONSTRUCTOR, METHOD;
   }
 
-  public static String computeFieldApiSignature(JField field) {
-    return field.getEnclosingType().getQualifiedSourceName() + "::"
-        + field.getName();
-  }
+  private HashMap<String, ApiField> apiFields = null;
 
   /**
-   * Assumption: Clients may sub-class an API class, but they will not add their
-   * class to the package.
+   * TODO (amitmanjhi): Toby felt that combining structures for storing
+   * MethodType and Constructors was unnecessary. In particular, the hashMap of
+   * name#args -> object is meaningless for constructor, since name is empty for
+   * constructors. Make it separate.
    * 
-   * Notes: -- A class with only private constructors can be an Api class.
+   * In addition, the current method fails when constructors or methods accept
+   * variable arguments. In future, just index everything by name [and not add
+   * the number of arguments that they accept].
    */
-  public static boolean isApiClass(JClassType classType) {
-    // check for outer classes
-    if (isPublicOuterClass(classType)) {
-      return true;
-    }
-    // if classType is not a member type, return false
-    if (!classType.isMemberType()) {
-      return false;
-    }
-    JClassType enclosingType = classType.getEnclosingType();
-    if (classType.isPublic()) {
-      return isApiClass(enclosingType) || isAnySubtypeAnApiClass(enclosingType);
-    }
-    if (classType.isProtected()) {
-      return isSubclassableApiClass(enclosingType)
-          || isAnySubtypeASubclassableApiClass(enclosingType);
-    }
-    return false;
-  }
-
-  public static boolean isInstantiableApiClass(JClassType classType) {
-    return !classType.isAbstract()
-        && hasPublicOrProtectedConstructor(classType);
-  }
-
-  public static boolean isNotsubclassableApiClass(JClassType classType) {
-    return isApiClass(classType) && !isSubclassable(classType);
-  }
-
-  /**
-   * @return returns true if classType is public AND an outer class
-   */
-  public static boolean isPublicOuterClass(JClassType classType) {
-    return classType.isPublic() && !classType.isMemberType();
-  }
-
-  public static boolean isSubclassable(JClassType classType) {
-    return !classType.isFinal() && hasPublicOrProtectedConstructor(classType);
-  }
-
-  public static boolean isSubclassableApiClass(JClassType classType) {
-    return isApiClass(classType) && isSubclassable(classType);
-  }
-
-  private static boolean hasPublicOrProtectedConstructor(JClassType classType) {
-    JConstructor[] constructors = classType.getConstructors();
-    for (JConstructor constructor : constructors) {
-      if (constructor.isPublic() || constructor.isProtected()) {
-        return true;
-      }
-    }
-    return false;
-  }
-
-  private static boolean isAnySubtypeAnApiClass(JClassType classType) {
-    JClassType subTypes[] = classType.getSubtypes();
-    for (JClassType tempType : subTypes) {
-      if (isApiClass(tempType)) {
-        return true;
-      }
-    }
-    return false;
-  }
-
-  private static boolean isAnySubtypeASubclassableApiClass(JClassType classType) {
-    JClassType subTypes[] = classType.getSubtypes();
-    for (JClassType tempType : subTypes) {
-      if (isSubclassableApiClass(tempType)) {
-        return true;
-      }
-    }
-    return false;
-  }
-
-  private HashMap<String, JField> apiFields = null;
 
   /**
    * 2 entries in the list: one for CONSTRUCTOR, and the other for METHOD. Each
    * entry is a mapping from MethodName#args to a set of ApiAbstractMethod
    */
-  private ArrayList<HashMap<String, HashSet<ApiAbstractMethod>>> apiMembersByName = new ArrayList<HashMap<String, HashSet<ApiAbstractMethod>>>(
-      MethodType.values().length);
+  private EnumMap<MethodType, Map<String, Set<ApiAbstractMethod>>> apiMembersByName =
+      null;
 
-  private ApiPackage apiPackage = null;
+  private final ApiPackage apiPackage;
+  private final JClassType classType;
 
-  private JClassType classType = null;
+  private final boolean isInstantiableApiClass;
+  private final boolean isNotsubclassableApiClass;
+  private final boolean isSubclassableApiClass;
+  private final TreeLogger logger;
 
-  private boolean isInstantiableApiClass = false;
-
-  private boolean isNotsubclassableApiClass = false;
-  private boolean isSubclassableApiClass = false;
-  private TreeLogger logger = null;
-
-  public ApiClass(JClassType classType, ApiPackage apiPackage) {
+  ApiClass(JClassType classType, ApiPackage apiPackage) {
     this.classType = classType;
     this.apiPackage = apiPackage;
     logger = apiPackage.getApiContainer().getLogger();
-    isSubclassableApiClass = isSubclassableApiClass(classType);
-    isNotsubclassableApiClass = isNotsubclassableApiClass(classType);
-    isInstantiableApiClass = isInstantiableApiClass(classType);
+    ApiContainer apiContainer = apiPackage.getApiContainer();
+    isSubclassableApiClass = apiContainer.isSubclassableApiClass(classType);
+    isNotsubclassableApiClass =
+        apiContainer.isNotsubclassableApiClass(classType);
+    isInstantiableApiClass = apiContainer.isInstantiableApiClass(classType);
   }
 
-  public <E> String computeRelativeSignature(E element) {
-    String signature = element.toString();
-    JClassType enclosingType = null;
-    if (element instanceof JField) {
-      JField field = (JField) element;
-      signature = field.getName();
-      enclosingType = field.getEnclosingType();
-    }
-    if (element instanceof JAbstractMethod) {
-      JAbstractMethod jam = (JAbstractMethod) element;
-      signature = ApiAbstractMethod.computeInternalSignature(jam);
-      enclosingType = jam.getEnclosingType();
-    }
-    if (ApiCompatibilityChecker.DEBUG) {
-      return classType.getQualifiedSourceName()
-          + "::"
-          + signature
-          + " defined in "
-          + (enclosingType == null ? "null enclosing type "
-              : enclosingType.getQualifiedSourceName());
-    }
-    return classType.getQualifiedSourceName() + "::" + signature;
+  public int compareTo(ApiClass other) {
+    return getName().compareTo(other.getName());
   }
 
-  public JField getApiFieldByName(String name) {
+  public String getRelativeSignature() {
+    return classType.getQualifiedSourceName();
+  }
+
+  @Override
+  public String toString() {
+    return classType.toString();
+  }
+
+  String getApiAsString() {
+    StringBuffer sb = new StringBuffer();
+    sb.append("\t" + getName() + "\n");
+    if (apiFields != null) {
+      ArrayList<ApiField> apiFieldsList =
+          new ArrayList<ApiField>(apiFields.values());
+      Collections.sort(apiFieldsList);
+      for (ApiField apiField : apiFieldsList) {
+        sb.append("\t\t" + apiField.getRelativeSignature() + "\n");
+      }
+    }
+    if (apiMembersByName != null
+        && apiMembersByName.get(MethodType.METHOD) != null) {
+      for (MethodType method : MethodType.values()) {
+        HashSet<ApiAbstractMethod> apiMethodsSet =
+            new HashSet<ApiAbstractMethod>();
+        for (Set<ApiAbstractMethod> methodsSets : apiMembersByName.get(method).values()) {
+          apiMethodsSet.addAll(methodsSets);
+        }
+        ArrayList<ApiAbstractMethod> apiMethodsList =
+            new ArrayList<ApiAbstractMethod>(apiMethodsSet);
+        Collections.sort(apiMethodsList);
+        for (ApiAbstractMethod apiMethod : apiMethodsList) {
+          sb.append("\t\t" + apiMethod.getRelativeSignature() + "\n");
+        }
+      }
+    }
+    return sb.toString();
+  }
+
+  ApiField getApiFieldByName(String name) {
     return apiFields.get(name);
   }
 
-  public HashSet<String> getApiFieldNames() {
+  Set<String> getApiFieldNames() {
     if (apiFields == null) {
       initializeApiFields();
     }
     return new HashSet<String>(apiFields.keySet());
   }
 
-  public HashSet<JField> getApiFieldsBySet(HashSet<String> names) {
-    HashSet<JField> ret = new HashSet<JField>();
-    String tempStrings[] = names.toArray(new String[0]);
-    for (String temp : tempStrings) {
-      ret.add(apiFields.get(temp));
+  Set<ApiField> getApiFieldsBySet(Set<String> names) {
+    Set<ApiField> ret = new HashSet<ApiField>();
+    for (String name : names) {
+      ret.add(apiFields.get(name));
     }
     return ret;
   }
 
-  public HashSet<String> getApiMemberNames(MethodType type) {
-    if (apiMembersByName.size() == 0) {
-      initializeApiConstructorsAndFields();
+  Set<String> getApiMemberNames(MethodType type) {
+    if (apiMembersByName == null) {
+      initializeApiConstructorsAndMethods();
     }
-    return new HashSet<String>(apiMembersByName.get(type.getId()).keySet());
+    return new HashSet<String>(apiMembersByName.get(type).keySet());
   }
 
-  public HashSet<ApiAbstractMethod> getApiMembersBySet(
-      HashSet<String> methodNames, MethodType type) {
-    Iterator<String> iteratorString = methodNames.iterator();
-    HashMap<String, HashSet<ApiAbstractMethod>> current = apiMembersByName.get(type.getId());
-    HashSet<ApiAbstractMethod> tempMethods = new HashSet<ApiAbstractMethod>();
-    while (iteratorString.hasNext()) {
-      tempMethods.addAll(current.get(iteratorString.next()));
+  Set<ApiAbstractMethod> getApiMembersBySet(Set<String> methodNames,
+      MethodType type) {
+    Map<String, Set<ApiAbstractMethod>> current = apiMembersByName.get(type);
+    Set<ApiAbstractMethod> tempMethods = new HashSet<ApiAbstractMethod>();
+    for (String methodName : methodNames) {
+      tempMethods.addAll(current.get(methodName));
     }
     return tempMethods;
   }
 
-  public HashSet<ApiAbstractMethod> getApiMethodsByName(String name,
-      MethodType type) {
-    return apiMembersByName.get(type.getId()).get(name);
+  Set<ApiAbstractMethod> getApiMethodsByName(String name, MethodType type) {
+    return apiMembersByName.get(type).get(name);
   }
 
-  public JClassType getClassObject() {
+  JClassType getClassObject() {
     return classType;
   }
 
-  public String getFullName() {
+  String getFullName() {
     return classType.getQualifiedSourceName();
   }
 
@@ -246,9 +180,9 @@
    * (if a non-abstract class is made into interface, the client class/interface
    * inheriting from it would need to change)
    */
-  public ArrayList<ApiChange.Status> getModifierChanges(ApiClass newClass) {
+  List<ApiChange.Status> getModifierChanges(ApiClass newClass) {
     JClassType newClassType = newClass.getClassObject();
-    ArrayList<ApiChange.Status> statuses = new ArrayList<ApiChange.Status>(5);
+    List<ApiChange.Status> statuses = new ArrayList<ApiChange.Status>(5);
 
     // check for addition of 'final', 'abstract', 'static'
     if (!classType.isFinal() && newClassType.isFinal()) {
@@ -269,7 +203,7 @@
     if (!classType.isAbstract() && (newClassType.isInterface() != null)) {
       statuses.add(ApiChange.Status.NONABSTRACT_CLASS_MADE_INTERFACE);
     }
-    if (isSubclassableApiClass(classType)) {
+    if (apiPackage.getApiContainer().isSubclassableApiClass(classType)) {
       if ((classType.isClass() != null) && (newClassType.isInterface() != null)) {
         statuses.add(ApiChange.Status.SUBCLASSABLE_API_CLASS_MADE_INTERFACE);
       }
@@ -280,21 +214,22 @@
     return statuses;
   }
 
-  public String getName() {
+  String getName() {
     return classType.getName();
   }
 
-  public ApiPackage getPackage() {
+  ApiPackage getPackage() {
     return apiPackage;
   }
 
-  public void initializeApiFields() {
-    apiFields = new HashMap<String, JField>();
-    ArrayList<String> notAddedFields = new ArrayList<String>();
+  void initializeApiFields() {
+    apiFields = new HashMap<String, ApiField>();
+    List<String> notAddedFields = new ArrayList<String>();
     JField fields[] = getAccessibleFields();
     for (JField field : fields) {
       if (isApiMember(field)) {
-        apiFields.put(computeFieldApiSignature(field), field);
+        apiFields.put(ApiField.computeApiSignature(field), new ApiField(field,
+            this));
       } else {
         notAddedFields.add(field.toString());
       }
@@ -305,11 +240,6 @@
     }
   }
 
-  @Override
-  public String toString() {
-    return classType.toString();
-  }
-
   private JField[] getAccessibleFields() {
     Map<String, JField> fieldsBySignature = new HashMap<String, JField>();
     JClassType tempClassType = classType;
@@ -331,16 +261,6 @@
     return fieldsBySignature.values().toArray(new JField[0]);
   }
 
-  private JAbstractMethod[] getAccessibleMembers(MethodType member) {
-    switch (member) {
-      case CONSTRUCTOR:
-        return classType.getConstructors();
-      case METHOD:
-        return getAccessibleMethods();
-    }
-    throw new AssertionError("Unknown value : " + member.getId());
-  }
-
   // TODO(amitmanjhi): to optimize, cache results
   private JMethod[] getAccessibleMethods() {
     boolean isInterface = false;
@@ -377,21 +297,35 @@
     return methodsBySignature.values().toArray(new JMethod[0]);
   }
 
-  private void initializeApiConstructorsAndFields() {
-    for (MethodType member : MethodType.values()) {
-      apiMembersByName.add(member.getId(),
-          new HashMap<String, HashSet<ApiAbstractMethod>>());
-      HashMap<String, HashSet<ApiAbstractMethod>> pointer = apiMembersByName.get(member.getId());
-      ArrayList<String> notAddedMembers = new ArrayList<String>();
-      JAbstractMethod jams[] = getAccessibleMembers(member);
+  private JAbstractMethod[] getAccessibleMethods(MethodType member) {
+    switch (member) {
+      case CONSTRUCTOR:
+        return classType.getConstructors();
+      case METHOD:
+        return getAccessibleMethods();
+    }
+    throw new AssertionError("Unknown value : " + member);
+  }
+
+  private void initializeApiConstructorsAndMethods() {
+    apiMembersByName =
+        new EnumMap<MethodType, Map<String, Set<ApiAbstractMethod>>>(
+            MethodType.class);
+    for (MethodType method : MethodType.values()) {
+      apiMembersByName.put(method,
+          new HashMap<String, Set<ApiAbstractMethod>>());
+      Map<String, Set<ApiAbstractMethod>> pointer =
+          apiMembersByName.get(method);
+      List<String> notAddedMembers = new ArrayList<String>();
+      JAbstractMethod jams[] = getAccessibleMethods(method);
       for (JAbstractMethod jam : jams) {
         if (isApiMember(jam)) {
           String tempName = jam.getName() + jam.getParameters().length;
-          HashSet<ApiAbstractMethod> existingMembers = pointer.get(tempName);
+          Set<ApiAbstractMethod> existingMembers = pointer.get(tempName);
           if (existingMembers == null) {
             existingMembers = new HashSet<ApiAbstractMethod>();
           }
-          switch (member) {
+          switch (method) {
             case CONSTRUCTOR:
               existingMembers.add(new ApiConstructor(jam, this));
               break;
@@ -399,7 +333,7 @@
               existingMembers.add(new ApiMethod(jam, this));
               break;
             default:
-              throw new AssertionError("Unknown memberType : " + member);
+              throw new AssertionError("Unknown memberType : " + method);
           }
           pointer.put(tempName, existingMembers);
         } else {
@@ -418,7 +352,7 @@
    * Note: Instance members of a class that is not instantiable are not api
    * members.
    */
-  private <E> boolean isApiMember(final E member) {
+  private boolean isApiMember(final Object member) {
     boolean isPublic = false;
     boolean isPublicOrProtected = false;
     boolean isStatic = false;
@@ -440,12 +374,13 @@
         isStatic = false; // constructors can't be static
       }
     }
-    if (ApiCompatibilityChecker.REMOVE_ABSTRACT_CLASS_FROM_API) {
-      if (!isInstantiableApiClass && !isStatic) {
+    if (ApiCompatibilityChecker.REMOVE_NON_SUBCLASSABLE_ABSTRACT_CLASS_FROM_API) {
+      if (!isInstantiableApiClass && !isStatic && !isSubclassableApiClass) {
         return false;
       }
     }
     return (isSubclassableApiClass && isPublicOrProtected)
         || (isNotsubclassableApiClass && isPublic);
   }
+
 }
diff --git a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiClassDiffGenerator.java b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiClassDiffGenerator.java
index ed607e0..d32b39f 100644
--- a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiClassDiffGenerator.java
+++ b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiClassDiffGenerator.java
@@ -16,67 +16,43 @@
 
 package com.google.gwt.tools.apichecker;
 
-import com.google.gwt.core.ext.typeinfo.JAbstractMethod;
 import com.google.gwt.core.ext.typeinfo.JClassType;
-import com.google.gwt.core.ext.typeinfo.JField;
 import com.google.gwt.core.ext.typeinfo.JType;
 import com.google.gwt.core.ext.typeinfo.NotFoundException;
 
 import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.EnumMap;
 import java.util.HashMap;
 import java.util.HashSet;
-import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
 
 /**
  * Produces the diff between the API of two apiClasses.
  */
-public class ApiClassDiffGenerator {
-  abstract static class DuplicateDetector<E> {
-    ApiDiffGenerator apiDiffGenerator;
-    JClassType currentClass;
-    int initialValue = 1;
-    ApiClass.MethodType methodType;
+final class ApiClassDiffGenerator implements Comparable<ApiClassDiffGenerator> {
 
-    DuplicateDetector(JClassType currentClass,
-        ApiDiffGenerator apiDiffGenerator, ApiClass.MethodType methodType) {
-      this.currentClass = currentClass;
-      this.apiDiffGenerator = apiDiffGenerator;
-      initialValue++;
-      this.methodType = methodType;
+  static final Collection<ApiChange> EMPTY_COLLECTION =
+      new ArrayList<ApiChange>(0);
+
+  static String printSetWithHashCode(Set<?> set, String identifier) {
+    StringBuffer sb = new StringBuffer();
+    sb.append(identifier + ", size = " + set.size());
+    for (Object element : set) {
+      sb.append(element + ", hashcode = " + element.hashCode());
     }
-
-    JClassType getClassType(E element) {
-      if (element instanceof JAbstractMethod) {
-        JAbstractMethod jam = (JAbstractMethod) element;
-        return jam.getEnclosingType();
-      }
-      if (element instanceof JField) {
-        JField field = (JField) element;
-        return field.getEnclosingType();
-      }
-      return null;
-    }
-
-    abstract HashSet<E> getElements(ApiClassDiffGenerator other);
-
-    boolean isDuplicate(E element) {
-      JClassType classType = getClassType(element);
-      if (classType == currentClass) {
-        return false;
-      }
-      ApiClassDiffGenerator other = apiDiffGenerator.findApiClassDiffGenerator(classType);
-      if (other == null) {
-        return false;
-      }
-      return getElements(other).contains(element);
-    }
+    sb.append("\n");
+    return sb.toString();
   }
 
-  private static ArrayList<ApiChange> checkExceptions(
-      JAbstractMethod newMethod, JAbstractMethod oldMethod) {
-    JType oldExceptions[] = oldMethod.getThrows();
-    JType newExceptions[] = newMethod.getThrows();
-    ArrayList<ApiChange> ret = new ArrayList<ApiChange>();
+  private static List<ApiChange> checkExceptions(ApiAbstractMethod newMethod,
+      ApiAbstractMethod oldMethod) {
+    JType newExceptions[] = newMethod.getMethod().getThrows();
+    JType oldExceptions[] = oldMethod.getMethod().getThrows();
+    List<ApiChange> ret = new ArrayList<ApiChange>();
     for (JType newException : newExceptions) {
       boolean isSubclass = false;
       for (JType oldException : oldExceptions) {
@@ -87,313 +63,206 @@
         }
       }
       if (!isSubclass) {
-        ret.add(new ApiChange(ApiChange.Status.EXCEPTIONS_ERROR,
-            "unhandled exception in new code " + newException.toString()));
+        ret.add(new ApiChange(oldMethod, ApiChange.Status.EXCEPTION_TYPE_ERROR,
+            "unhandled exception in new code " + newException));
       }
     }
     return ret;
   }
 
-  HashSet<JField> allIntersectingFields = new HashSet<JField>();
-
+  private Set<ApiField> allIntersectingFields = new HashSet<ApiField>();
   /**
    * Find all constructors, methods, fields that are present in either
    * intersection or missing members of this class or any superclass. Total of 6
    * things to keep track of. These variables are useful for memoization.
    */
-  ArrayList<HashSet<JAbstractMethod>> allIntersectingMethods = new ArrayList<HashSet<JAbstractMethod>>(
-      2);
+  private EnumMap<ApiClass.MethodType, Set<ApiAbstractMethod>> allIntersectingMethods =
+      null;
 
-  ArrayList<HashSet<JAbstractMethod>> allMissingMethods = new ArrayList<HashSet<JAbstractMethod>>(
-      2);
-  ApiDiffGenerator apiDiffGenerator = null;
-  ApiPackageDiffGenerator apiPackageDiffGenerator = null;
-  String className = null;
+  private Set<ApiField> allMissingFields = null;
+  private EnumMap<ApiClass.MethodType, Set<ApiAbstractMethod>> allMissingMethods =
+      null;
 
-  HashMap<JField, HashSet<ApiChange.Status>> intersectingFields = null;
+  private final ApiDiffGenerator apiDiffGenerator;
+  private final String className;
+  private HashMap<ApiField, Set<ApiChange.Status>> intersectingFields = null;
 
   /**
    * Map from methods and constructors in intersection to a string describing
    * how they have changed. The description could be the addition/removal of a
    * static/abstract/final keyword.
    */
-  ArrayList<HashMap<JAbstractMethod, HashSet<ApiChange>>> intersectingMethods;
-  HashSet<JField> missingFields = null;
+  private EnumMap<ApiClass.MethodType, Map<ApiAbstractMethod, Set<ApiChange>>> intersectingMethods;
+  private Set<ApiField> missingFields = null;
   /**
    * list of missing constructors and methods.
    */
-  ArrayList<HashSet<JAbstractMethod>> missingMethods;
-  ApiClass newClass = null;
+  private EnumMap<ApiClass.MethodType, Set<ApiAbstractMethod>> missingMethods;
+  private final ApiClass newClass;
 
-  ApiClass oldClass = null;
-  private HashSet<JField> allMissingFields = new HashSet<JField>();
+  private final ApiClass oldClass;
 
-  public ApiClassDiffGenerator(String className,
+  ApiClassDiffGenerator(String className,
       ApiPackageDiffGenerator apiPackageDiffGenerator) throws NotFoundException {
     this.className = className;
-    this.apiPackageDiffGenerator = apiPackageDiffGenerator;
     apiDiffGenerator = apiPackageDiffGenerator.getApiDiffGenerator();
-    this.newClass = apiPackageDiffGenerator.getNewApiPackage().getApiClass(
-        className);
-    this.oldClass = apiPackageDiffGenerator.getOldApiPackage().getApiClass(
-        className);
+    this.newClass =
+        apiPackageDiffGenerator.getNewApiPackage().getApiClass(className);
+    this.oldClass =
+        apiPackageDiffGenerator.getOldApiPackage().getApiClass(className);
     if (newClass == null || oldClass == null) {
       throw new NotFoundException("for class " + className
           + ", one of the class objects is null");
     }
-    intersectingFields = new HashMap<JField, HashSet<ApiChange.Status>>();
-    intersectingMethods = new ArrayList<HashMap<JAbstractMethod, HashSet<ApiChange>>>(
-        ApiClass.MethodType.values().length);
-    missingMethods = new ArrayList<HashSet<JAbstractMethod>>(
-        ApiClass.MethodType.values().length);
+
+    intersectingFields = new HashMap<ApiField, Set<ApiChange.Status>>();
+    intersectingMethods =
+        new EnumMap<ApiClass.MethodType, Map<ApiAbstractMethod, Set<ApiChange>>>(
+            ApiClass.MethodType.class);
+    missingMethods =
+        new EnumMap<ApiClass.MethodType, Set<ApiAbstractMethod>>(
+            ApiClass.MethodType.class);
     for (ApiClass.MethodType methodType : ApiClass.MethodType.values()) {
-      intersectingMethods.add(methodType.getId(),
-          new HashMap<JAbstractMethod, HashSet<ApiChange>>());
+      intersectingMethods.put(methodType,
+          new HashMap<ApiAbstractMethod, Set<ApiChange>>());
     }
   }
 
-  public void cleanApiDiff() {
-    /**
-     * Two different ways of eliminating duplicates from apiDiffs. 1.
-     * computeUnionsAndCleandApiDiff: remove an ApiDiff message from this class,
-     * if it is present in the apiDiffs of any of the superclasses. (Not sure if
-     * the implementation always yield the correct result. Therefore, I have not
-     * removed the cleanApiDiff2 implementation.)
-     * 
-     * 2. cleanApiDiff2: If the ApiDiff message is about member 'x', remove the
-     * ApiDiff message from this class, if the class defining 'x' also contains
-     * this message.
-     */
-    if (true) {
-      computeUnionsAndCleanApiDiff();
-    } else {
-      cleanApiDiff2();
-    }
-  }
-
-  public void cleanApiDiff2() {
-    DuplicateDetector<JField> fieldRemover = new DuplicateDetector<JField>(
-        oldClass.getClassObject(), apiDiffGenerator,
-        ApiClass.MethodType.CONSTRUCTOR) {
-      @Override
-      HashSet<JField> getElements(ApiClassDiffGenerator other) {
-        return other.getMissingFields();
-      }
-    };
-    missingFields.removeAll(getDuplicateElements(missingFields.iterator(),
-        fieldRemover));
-
-    DuplicateDetector<JField> intersectingFieldRemover = new DuplicateDetector<JField>(
-        oldClass.getClassObject(), apiDiffGenerator,
-        ApiClass.MethodType.CONSTRUCTOR) {
-      @Override
-      HashSet<JField> getElements(ApiClassDiffGenerator other) {
-        return other.getIntersectingFields();
-      }
-    };
-    removeAll(intersectingFields, getDuplicateElements(
-        intersectingFields.keySet().iterator(), intersectingFieldRemover));
-
-    for (ApiClass.MethodType methodType : ApiClass.MethodType.values()) {
-      DuplicateDetector<JAbstractMethod> missingMemberRemover = new DuplicateDetector<JAbstractMethod>(
-          oldClass.getClassObject(), apiDiffGenerator, methodType) {
-        @Override
-        HashSet<JAbstractMethod> getElements(final ApiClassDiffGenerator other) {
-          return other.getMissingMethods(methodType);
-        }
-      };
-      missingMethods.get(methodType.getId()).removeAll(
-          getDuplicateElements(
-              missingMethods.get(methodType.getId()).iterator(),
-              missingMemberRemover));
-
-      DuplicateDetector<JAbstractMethod> intersectingMemberRemover = new DuplicateDetector<JAbstractMethod>(
-          oldClass.getClassObject(), apiDiffGenerator, methodType) {
-        @Override
-        HashSet<JAbstractMethod> getElements(final ApiClassDiffGenerator other) {
-          return other.getIntersectingMethods(methodType);
-        }
-      };
-      removeAll(intersectingMethods.get(methodType.getId()),
-          getDuplicateElements(
-              intersectingMethods.get(methodType.getId()).keySet().iterator(),
-              intersectingMemberRemover));
-    }
-  }
-
-  public void computeApiDiff() {
-    HashSet<String> newFieldNames = newClass.getApiFieldNames();
-    HashSet<String> oldFieldNames = oldClass.getApiFieldNames();
-    HashSet<String> intersection = ApiDiffGenerator.extractCommonElements(
-        newFieldNames, oldFieldNames);
-    missingFields = oldClass.getApiFieldsBySet(oldFieldNames);
-    processFieldsInIntersection(intersection);
-
-    for (ApiClass.MethodType methodType : ApiClass.MethodType.values()) {
-      HashSet<String> newMethodNames = newClass.getApiMemberNames(methodType);
-      HashSet<String> oldMethodNames = oldClass.getApiMemberNames(methodType);
-      intersection = ApiDiffGenerator.extractCommonElements(newMethodNames,
-          oldMethodNames);
-      missingMethods.add(methodType.getId(),
-          getAbstractMethodObjects(oldClass.getApiMembersBySet(oldMethodNames,
-              methodType)));
-      processElementsInIntersection(intersection, methodType);
-    }
+  /*
+   * (non-Javadoc)
+   * 
+   * @see java.lang.Comparable#compareTo(java.lang.Object)
+   */
+  public int compareTo(ApiClassDiffGenerator other) {
+    return getName().compareTo(other.getName());
   }
 
   /**
-   * Compute the union of apiDiffs of all superclasses. Must be invoked only
-   * after intersectingMembers et al. have been computed. Algorithm: - Find the
-   * immediate superclass that has computed these apiDiffs. - Compute the union
-   * of apiDiffs of superClass with own apiDiffs.
+   * 
+   * cleanApiDiff: remove an ApiDiff message from this class, if it is present
+   * in the apiDiffs of any of the super-classes.
+   * 
+   * Compute the union of apiDiffs of all superclasses as part of this method.
+   * Must be invoked only after intersectingMembers et al. have been computed.
+   * Algorithm: - Find the immediate superclass that has computed these
+   * apiDiffs. - Compute the union of apiDiffs of superClass with own apiDiffs.
    */
-  public void computeUnionsAndCleanApiDiff() {
+  void cleanApiDiff() {
     // check if unions have already been computed.
-    if (allMissingMethods.size() > 0) {
+    if (allMissingMethods != null) {
       return;
     }
     ApiClassDiffGenerator other = getSuperclassApiClassDiffGenerator();
     // compute 'all*' fields for the 'other' object.
     if (other != null) {
-      other.computeUnionsAndCleanApiDiff();
+      other.cleanApiDiff();
     }
+    allIntersectingMethods =
+        new EnumMap<ApiClass.MethodType, Set<ApiAbstractMethod>>(
+            ApiClass.MethodType.class);
+    allMissingMethods =
+        new EnumMap<ApiClass.MethodType, Set<ApiAbstractMethod>>(
+            ApiClass.MethodType.class);
 
     for (ApiClass.MethodType methodType : ApiClass.MethodType.values()) {
-      // clean the current apiDiffs
+      // for methods/constructors: clean the current apiDiffs
       if (other != null) {
-        removeAll(intersectingMethods.get(methodType.getId()),
-            other.allIntersectingMethods.get(methodType.getId()));
-        missingMethods.get(methodType.getId()).removeAll(
-            other.allMissingMethods.get(methodType.getId()));
+        removeAll(intersectingMethods.get(methodType),
+            other.allIntersectingMethods.get(methodType));
+        missingMethods.get(methodType).removeAll(
+            other.allMissingMethods.get(methodType));
       }
-      // compute the union
-      HashSet<JAbstractMethod> tempSet1 = new HashSet<JAbstractMethod>(
-          intersectingMethods.get(methodType.getId()).keySet());
-      HashSet<JAbstractMethod> tempSet2 = new HashSet<JAbstractMethod>(
-          missingMethods.get(methodType.getId()));
+      // for methods/constructors: compute the allIntersecting*, allMissing*
+      HashSet<ApiAbstractMethod> tempSet1 =
+          new HashSet<ApiAbstractMethod>(
+              intersectingMethods.get(methodType).keySet());
+      HashSet<ApiAbstractMethod> tempSet2 =
+          new HashSet<ApiAbstractMethod>(missingMethods.get(methodType));
       if (other != null) {
-        tempSet1.addAll(other.allIntersectingMethods.get(methodType.getId()));
-        tempSet2.addAll(other.allMissingMethods.get(methodType.getId()));
+        tempSet1.addAll(other.allIntersectingMethods.get(methodType));
+        tempSet2.addAll(other.allMissingMethods.get(methodType));
       }
-      allIntersectingMethods.add(methodType.getId(), tempSet1);
-      allMissingMethods.add(methodType.getId(), tempSet2);
+      allIntersectingMethods.put(methodType, tempSet1);
+      allMissingMethods.put(methodType, tempSet2);
     }
-    // clean the current apiDiffs
+
+    // for fields: clean the current apiDiffs
     if (other != null) {
       removeAll(intersectingFields, other.allIntersectingFields);
       missingFields.removeAll(other.allMissingFields);
     }
-    // compute the union
-    allIntersectingFields = new HashSet<JField>(intersectingFields.keySet());
-    allMissingFields = new HashSet<JField>(missingFields);
+    // for fields: compute allIntersectingFields, allMissingFields
+    allIntersectingFields = new HashSet<ApiField>(intersectingFields.keySet());
+    allMissingFields = new HashSet<ApiField>(missingFields);
     if (other != null) {
       allIntersectingFields.addAll(other.allIntersectingFields);
       allMissingFields.addAll(other.allMissingFields);
     }
   }
 
-  public HashSet<JAbstractMethod> getAbstractMethodObjects(
-      HashSet<? extends ApiAbstractMethod> temp) {
-    Iterator<? extends ApiAbstractMethod> apiMethodsIterator = temp.iterator();
-    HashSet<JAbstractMethod> returnSet = new HashSet<JAbstractMethod>();
-    while (apiMethodsIterator.hasNext()) {
-      returnSet.add(apiMethodsIterator.next().getMethodObject());
-    }
-    return returnSet;
-  }
+  // TODO(amitmanjhi): for methods, think about variable length arguments
+  void computeApiDiff() {
+    Set<String> newFieldNames = newClass.getApiFieldNames();
+    Set<String> oldFieldNames = oldClass.getApiFieldNames();
+    Set<String> intersection =
+        ApiDiffGenerator.removeIntersection(newFieldNames, oldFieldNames);
+    missingFields = oldClass.getApiFieldsBySet(oldFieldNames);
+    processFieldsInIntersection(intersection);
 
-  public <T> HashSet<T> getDuplicateElements(Iterator<T> iterator,
-      DuplicateDetector<T> detector) {
-    HashSet<T> returnSet = new HashSet<T>();
-    while (iterator.hasNext()) {
-      T element = iterator.next();
-      if (detector.isDuplicate(element)) {
-        returnSet.add(element);
-      }
-    }
-    return returnSet;
-  }
-
-  public HashSet<JField> getIntersectingFields() {
-    return new HashSet<JField>(intersectingFields.keySet());
-  }
-
-  public HashSet<JAbstractMethod> getIntersectingMethods(
-      ApiClass.MethodType methodType) {
-    return new HashSet<JAbstractMethod>(intersectingMethods.get(
-        methodType.getId()).keySet());
-  }
-
-  public HashSet<JField> getMissingFields() {
-    return missingFields;
-  }
-
-  public HashSet<JAbstractMethod> getMissingMethods(
-      ApiClass.MethodType methodType) {
-    return missingMethods.get(methodType.getId());
-  }
-
-  public HashSet<ApiChange.Status> getModifierChangesForField(JField newField,
-      JField oldField) {
-    HashSet<ApiChange.Status> statuses = new HashSet<ApiChange.Status>();
-    if (!oldField.isFinal() && newField.isFinal()) {
-      statuses.add(ApiChange.Status.FINAL_ADDED);
-    }
-    if ((oldField.isStatic() && !newField.isStatic())) {
-      statuses.add(ApiChange.Status.STATIC_REMOVED);
-    }
-    return statuses;
-  }
-
-  public String printApiDiff() {
-    ArrayList<ApiChange.Status> apiChanges = oldClass.getModifierChanges(newClass);
-    int totalSize = missingFields.size() + intersectingFields.size()
-        + apiChanges.size();
     for (ApiClass.MethodType methodType : ApiClass.MethodType.values()) {
-      totalSize += (missingMethods.get(methodType.getId()).size() + intersectingMethods.get(
-          methodType.getId()).size());
+      Set<String> newMethodNames = newClass.getApiMemberNames(methodType);
+      Set<String> oldMethodNames = oldClass.getApiMemberNames(methodType);
+      intersection =
+          ApiDiffGenerator.removeIntersection(newMethodNames, oldMethodNames);
+      missingMethods.put(methodType, oldClass.getApiMembersBySet(
+          oldMethodNames, methodType));
+      processElementsInIntersection(intersection, methodType);
     }
-    if (totalSize == 0) {
-      return "";
+  }
+
+  Collection<ApiChange> getApiDiff() {
+    Collection<ApiChange.Status> apiStatusChanges =
+        oldClass.getModifierChanges(newClass);
+    /*
+     * int totalSize = missingFields.size() + intersectingFields.size() +
+     * apiStatusChanges.size(); for (ApiClass.MethodType methodType :
+     * ApiClass.MethodType.values()) { totalSize +=
+     * (missingMethods.get(methodType).size() + intersectingMethods.get(
+     * methodType).size()); } if (totalSize == 0) { return EMPTY_COLLECTION; }
+     */
+    Collection<ApiChange> apiChangeCollection = new ArrayList<ApiChange>();
+    for (ApiChange.Status apiStatus : apiStatusChanges) {
+      apiChangeCollection.add(new ApiChange(oldClass, apiStatus));
     }
-    StringBuffer sb = new StringBuffer();
-    Iterator<ApiChange.Status> apiChangeIterator = apiChanges.iterator();
-    while (apiChangeIterator.hasNext()) {
-      sb.append("\t\t" + oldClass.getFullName() + " "
-          + apiChangeIterator.next() + "\n");
+    // missing fields
+    for (ApiElement element : missingFields) {
+      apiChangeCollection.add(new ApiChange(element, ApiChange.Status.MISSING));
     }
-    if (apiChanges.size() == 0) {
-      sb.append("\t\tclass " + oldClass.getFullName() + "\n");
-    }
-    sb.append(printCollectionElements(missingFields.iterator()));
-    sb.append(printCollectionElements2(intersectingFields));
+    apiChangeCollection.addAll(getIntersectingFields());
     for (ApiClass.MethodType methodType : ApiClass.MethodType.values()) {
-      sb.append(printCollectionElements(missingMethods.get(methodType.getId()).iterator()));
-      sb.append(printCollectionElements(intersectingMethods.get(methodType.getId())));
+      apiChangeCollection.addAll(getMissingMethods(methodType));
+      apiChangeCollection.addAll(getIntersectingMethods(methodType));
     }
-    sb.append("\n");
-    return sb.toString();
+    return apiChangeCollection;
   }
 
-  public <E, V> void removeAll(HashMap<E, HashSet<V>> tempMap,
-      HashSet<E> removeKeys) {
-    Iterator<E> keyIterator = removeKeys.iterator();
-    while (keyIterator.hasNext()) {
-      tempMap.remove(keyIterator.next());
-    }
+  String getName() {
+    return className;
   }
 
-  private <T> void addProperty(HashMap<T, HashSet<ApiChange>> hashMap, T key,
+  /*
+   * Even though the method name is contained in the "property" parameter, the
+   * type information is lost. TODO (amitmanjhi): fix this issue later.
+   */
+  private <T> void addProperty(Map<T, Set<ApiChange>> hashMap, T key,
       ApiChange property) {
-    if (!ApiCompatibilityChecker.PRINT_INTERSECTIONS
-        && (property.getStatus() == ApiChange.Status.COMPATIBLE)) {
-      return;
-    }
-    if (!ApiCompatibilityChecker.PRINT_COMPATIBLE_WITH
-        && property.getStatus() == ApiChange.Status.COMPATIBLE_WITH) {
-      return;
-    }
-    HashSet<ApiChange> value = hashMap.get(key);
+    /*
+     * if (!ApiCompatibilityChecker.PRINT_COMPATIBLE && (property.getStatus() ==
+     * ApiChange.Status.COMPATIBLE)) { return; } if
+     * (!ApiCompatibilityChecker.PRINT_COMPATIBLE_WITH && property.getStatus() ==
+     * ApiChange.Status.COMPATIBLE_WITH) { return; }
+     */
+    Set<ApiChange> value = hashMap.get(key);
     if (value == null) {
       value = new HashSet<ApiChange>();
     }
@@ -401,6 +270,43 @@
     hashMap.put(key, value);
   }
 
+  private Collection<ApiChange> getIntersectingFields() {
+    Collection<ApiChange> collection = new ArrayList<ApiChange>();
+    List<ApiField> intersectingFieldsList =
+        new ArrayList<ApiField>(intersectingFields.keySet());
+    Collections.sort(intersectingFieldsList);
+    for (ApiField apiField : intersectingFieldsList) {
+      for (ApiChange.Status status : intersectingFields.get(apiField)) {
+        collection.add(new ApiChange(apiField, status));
+      }
+    }
+    return collection;
+  }
+
+  private Collection<ApiChange> getIntersectingMethods(
+      ApiClass.MethodType methodType) {
+    Collection<ApiChange> collection = new ArrayList<ApiChange>();
+    List<ApiAbstractMethod> apiMethodsList =
+        new ArrayList<ApiAbstractMethod>(
+            intersectingMethods.get(methodType).keySet());
+    Collections.sort(apiMethodsList);
+    for (ApiAbstractMethod apiMethod : apiMethodsList) {
+      collection.addAll(intersectingMethods.get(methodType).get(apiMethod));
+    }
+    return collection;
+  }
+
+  private Collection<ApiChange> getMissingMethods(ApiClass.MethodType methodType) {
+    Collection<ApiChange> collection = new ArrayList<ApiChange>();
+    List<ApiAbstractMethod> apiMethodsList =
+        new ArrayList<ApiAbstractMethod>(missingMethods.get(methodType));
+    Collections.sort(apiMethodsList);
+    for (ApiAbstractMethod apiMethod : apiMethodsList) {
+      collection.add(new ApiChange(apiMethod, ApiChange.Status.MISSING));
+    }
+    return collection;
+  }
+
   /**
    * return the ApiClassDiffGenerator object for the "closest" ancestor of
    * oldClass. return null if no ancestor of oldClass has ApiClassDiffGenerator
@@ -409,7 +315,8 @@
     ApiClassDiffGenerator other = null;
     JClassType classType = oldClass.getClassObject();
     while ((classType = classType.getSuperclass()) != null) {
-      other = apiDiffGenerator.findApiClassDiffGenerator(classType);
+      other =
+          apiDiffGenerator.findApiClassDiffGenerator(classType.getQualifiedSourceName());
       if (other != null) {
         return other;
       }
@@ -418,17 +325,16 @@
   }
 
   private boolean isIncompatibileDueToMethodOverloading(
-      HashSet<ApiAbstractMethod> methodsInNew,
-      HashSet<ApiAbstractMethod> methodsInExisting) {
+      Set<ApiAbstractMethod> methodsInNew,
+      Set<ApiAbstractMethod> methodsInExisting) {
     if (!ApiCompatibilityChecker.API_SOURCE_COMPATIBILITY
         || methodsInExisting.size() != 1 || methodsInNew.size() <= 1) {
       return false;
     }
-    String signature = methodsInExisting.toArray(new ApiAbstractMethod[0])[0].getCoarseSignature();
-    Iterator<ApiAbstractMethod> newMethodsIterator = methodsInNew.iterator();
+    String signature =
+        methodsInExisting.toArray(new ApiAbstractMethod[0])[0].getCoarseSignature();
     int numMatchingSignature = 0;
-    while (newMethodsIterator.hasNext() && numMatchingSignature < 2) {
-      ApiAbstractMethod current = newMethodsIterator.next();
+    for (ApiAbstractMethod current : methodsInNew) {
       if (current.getCoarseSignature().equals(signature)) {
         ++numMatchingSignature;
       }
@@ -436,105 +342,50 @@
     return numMatchingSignature > 1;
   }
 
-  private <V> String printCollectionElements(
-      HashMap<JAbstractMethod, HashSet<V>> tempHashMap) {
-    StringBuffer sb = new StringBuffer();
-    Iterator<JAbstractMethod> tempIterator = tempHashMap.keySet().iterator();
-    while (tempIterator.hasNext()) {
-      JAbstractMethod element = tempIterator.next();
-      String identifier = oldClass.computeRelativeSignature(element);
-      Iterator<V> tempIterator2 = tempHashMap.get(element).iterator();
-      while (tempIterator2.hasNext()) {
-        sb.append("\t\t\t" + identifier + ApiDiffGenerator.DELIMITER
-            + tempIterator2.next() + "\n");
-      }
-    }
-    return sb.toString();
-  }
-
-  private <E> String printCollectionElements(Iterator<E> temp) {
-    StringBuffer sb = new StringBuffer();
-    while (temp.hasNext()) {
-      sb.append("\t\t\t" + oldClass.computeRelativeSignature(temp.next())
-          + ApiDiffGenerator.DELIMITER + ApiChange.Status.MISSING + "\n");
-    }
-    return sb.toString();
-  }
-
-  private <V> String printCollectionElements2(
-      HashMap<JField, HashSet<V>> tempHashMap) {
-    StringBuffer sb = new StringBuffer();
-    Iterator<JField> tempIterator = tempHashMap.keySet().iterator();
-    while (tempIterator.hasNext()) {
-      JField element = tempIterator.next();
-      String identifier = oldClass.computeRelativeSignature(element);
-      Iterator<V> tempIterator2 = tempHashMap.get(element).iterator();
-      while (tempIterator2.hasNext()) {
-        sb.append("\t\t\t" + identifier + ApiDiffGenerator.DELIMITER
-            + tempIterator2.next() + "\n");
-      }
-    }
-    return sb.toString();
-  }
-
-  private void processElementsInIntersection(HashSet<String> intersection,
+  private void processElementsInIntersection(Set<String> intersection,
       ApiClass.MethodType methodType) {
-    if (intersection.size() == 0) {
-      return;
-    }
-    HashSet<JAbstractMethod> missingElements = missingMethods.get(methodType.getId());
-    HashMap<JAbstractMethod, HashSet<ApiChange>> intersectingElements = intersectingMethods.get(methodType.getId());
 
-    HashSet<ApiAbstractMethod> onlyInExisting = new HashSet<ApiAbstractMethod>();
-    HashSet<ApiAbstractMethod> onlyInNew = new HashSet<ApiAbstractMethod>();
-    HashSet<String> commonSignature = new HashSet<String>();
-    Iterator<String> intersectionNames = intersection.iterator();
+    Set<ApiAbstractMethod> missingElements = missingMethods.get(methodType);
+    Map<ApiAbstractMethod, Set<ApiChange>> intersectingElements =
+        intersectingMethods.get(methodType);
 
-    while (intersectionNames.hasNext()) {
-      String tempName = intersectionNames.next();
-      HashSet<ApiAbstractMethod> methodsInNew = newClass.getApiMethodsByName(
-          tempName, methodType);
-      HashSet<ApiAbstractMethod> methodsInExisting = oldClass.getApiMethodsByName(
-          tempName, methodType);
+    Set<ApiAbstractMethod> onlyInExisting = new HashSet<ApiAbstractMethod>();
+    Set<ApiAbstractMethod> onlyInNew = new HashSet<ApiAbstractMethod>();
+    Set<String> commonSignature = new HashSet<String>();
+
+    for (String elementName : intersection) {
+      Set<ApiAbstractMethod> methodsInNew =
+          newClass.getApiMethodsByName(elementName, methodType);
+      Set<ApiAbstractMethod> methodsInExisting =
+          oldClass.getApiMethodsByName(elementName, methodType);
       onlyInNew.addAll(methodsInNew);
       onlyInExisting.addAll(methodsInExisting);
       if (isIncompatibileDueToMethodOverloading(methodsInNew, methodsInExisting)) {
-        addProperty(
-            intersectingElements,
-            methodsInExisting.toArray(new ApiAbstractMethod[0])[0].getMethodObject(),
-            new ApiChange(ApiChange.Status.OVERLOADED,
-                "Many methods in the new API with similar signatures. Methods = "
-                    + methodsInNew
-                    + " This might break API source compatibility"));
+        ApiAbstractMethod methodInExisting =
+            methodsInExisting.toArray(new ApiAbstractMethod[0])[0];
+        addProperty(intersectingElements, methodInExisting, new ApiChange(
+            methodInExisting, ApiChange.Status.OVERLOADED_METHOD_CALL,
+            "Many methods in the new API with similar signatures. Methods = "
+                + methodsInNew + " This might break API source compatibility"));
       }
-      Iterator<ApiAbstractMethod> iterator1 = methodsInExisting.iterator();
       // We want to find out which method calls that the current API supports
       // will succeed even with the new API. Determine this by iterating over
       // the methods of the current API
-      while (iterator1.hasNext()) {
-        ApiAbstractMethod methodInExisting = iterator1.next();
-        Iterator<ApiAbstractMethod> iterator2 = methodsInNew.iterator();
-        while (iterator2.hasNext()) {
-          ApiAbstractMethod methodInNew = iterator2.next();
+      for (ApiAbstractMethod methodInExisting : methodsInExisting) {
+        for (ApiAbstractMethod methodInNew : methodsInNew) {
           if (methodInExisting.isCompatible(methodInNew)) {
-            ApiChange returnType = methodInExisting.checkReturnTypeCompatibility(methodInNew);
+            ApiChange returnType =
+                methodInExisting.checkReturnTypeCompatibility(methodInNew);
             if (returnType != null) {
-              addProperty(intersectingElements,
-                  methodInExisting.getMethodObject(), returnType);
+              addProperty(intersectingElements, methodInExisting, returnType);
             }
-            Iterator<ApiChange> apiChangeIterator = checkExceptions(
-                methodInNew.getMethodObject(),
-                methodInExisting.getMethodObject()).iterator();
-            while (apiChangeIterator.hasNext()) {
-              addProperty(intersectingElements,
-                  methodInExisting.getMethodObject(), apiChangeIterator.next());
+            for (ApiChange apiChange : checkExceptions(methodInNew,
+                methodInExisting)) {
+              addProperty(intersectingElements, methodInExisting, apiChange);
             }
-            Iterator<ApiChange.Status> apiChanges = methodInExisting.getModifierChanges(
-                methodInNew).iterator();
-            while (apiChanges.hasNext()) {
-              addProperty(intersectingElements,
-                  methodInExisting.getMethodObject(), new ApiChange(
-                      apiChanges.next()));
+            for (ApiChange.Status status : methodInExisting.getModifierChanges(methodInNew)) {
+              addProperty(intersectingElements, methodInExisting,
+                  new ApiChange(methodInExisting, status));
             }
             onlyInNew.remove(methodInNew);
             onlyInExisting.remove(methodInExisting);
@@ -542,40 +393,36 @@
             String signatureInExisting = methodInExisting.getApiSignature();
             if (signatureInNew.equals(signatureInExisting)) {
               commonSignature.add(signatureInNew);
-              addProperty(intersectingElements,
-                  methodInExisting.getMethodObject(), new ApiChange(
-                      ApiChange.Status.COMPATIBLE));
+              addProperty(intersectingElements, methodInExisting,
+                  new ApiChange(methodInExisting, ApiChange.Status.COMPATIBLE));
             } else {
-              addProperty(intersectingElements,
-                  methodInExisting.getMethodObject(), new ApiChange(
-                      ApiChange.Status.COMPATIBLE_WITH, " compatible with "
-                          + signatureInNew));
+              addProperty(intersectingElements, methodInExisting,
+                  new ApiChange(methodInExisting,
+                      ApiChange.Status.COMPATIBLE_WITH, signatureInNew));
             }
           }
         }
       }
       // printOutput(commonSignature, onlyInExisting, onlyInNew);
     }
-    missingElements.addAll(getAbstractMethodObjects(onlyInExisting));
+    missingElements.addAll(onlyInExisting);
   }
 
-  private void processFieldsInIntersection(HashSet<String> intersection) {
-    if (intersection.size() == 0) {
-      return;
-    }
-    Iterator<String> intersectionNames = intersection.iterator();
-
-    while (intersectionNames.hasNext()) {
-      String tempName = intersectionNames.next();
-      JField newField = newClass.getApiFieldByName(tempName);
-      JField oldField = oldClass.getApiFieldByName(tempName);
-      HashSet<ApiChange.Status> apiChanges = getModifierChangesForField(
-          newField, oldField);
+  private void processFieldsInIntersection(Set<String> intersection) {
+    for (String fieldName : intersection) {
+      ApiField newField = newClass.getApiFieldByName(fieldName);
+      ApiField oldField = oldClass.getApiFieldByName(fieldName);
+      Set<ApiChange.Status> apiChanges = oldField.getModifierChanges(newField);
       if (apiChanges.size() > 0) {
-        intersectingFields.put(oldField, getModifierChangesForField(newField,
-            oldField));
+        intersectingFields.put(oldField, apiChanges);
       }
     }
   }
 
+  private <E, V> void removeAll(Map<E, Set<V>> tempMap, Set<E> removeKeys) {
+    for (E element : removeKeys) {
+      tempMap.remove(element);
+    }
+  }
+
 }
diff --git a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiCompatibilityChecker.java b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiCompatibilityChecker.java
index 8489d8b..631f64a 100644
--- a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiCompatibilityChecker.java
+++ b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiCompatibilityChecker.java
@@ -23,54 +23,92 @@
 import java.io.BufferedReader;
 import java.io.FileReader;
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
 import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
 
 /**
- * Checks if the new API is compatible with the existing API.
+ * {@link ApiCompatibilityChecker} Main class to check if the new API is
+ * compatible with the existing API.
  * 
  * 
- * To compute Api diffs, follow these 5 steps: i) for each of the two
- * repositories, construct an ApiContainer, ii) construct an ApiDiffGenerator,
- * iii) call computeApiDiff on the ApiDiffGenerator iv) call cleanApiDiff on the
- * ApiDiffGenerator v) call printApiDiff on the ApiDiffGenerator
+ * <p>
+ * To compute API diffs, follow these 2 steps:
+ * <ol>
+ * <li> for each of the two repositories, construct an {@link ApiContainer}
+ * <li> call getApiDiff on the {@code ApiDiffGenerator}
+ * </ol>
+ * </p>
  * 
- * An apicontainer object has a list of apiPackage objects. ApiPackage objects
- * themselves are list of ApiClass objects. ApiClass objects contain list of
- * ApiConstructor, ApiMethod, and JField objects.
+ * <p>
+ * An {@code ApiContainer} object is a list of {@link ApiPackage} objects.
+ * {@code ApiPackage} objects themselves are list of {@link ApiClass} objects.
+ * {@code ApiClass} objects contain list of {@code ApiConstructor},
+ * {@code ApiMethod}, and {@code JField} objects.
+ * </p>
  * 
- * Each ApiDiffGenerator object has a list of intersecting and missing
- * ApiPackageDiffGenerator objects. Each ApiPackageDiffGenerator object has a
- * list of intersecting and missing ApiClassDiffGenerator objects. Each
- * ApiClassDiffGenerator object has a list of intersecting and missing
- * apiMembers, where these members are constructors, methods, and fields.
+ * <p>
+ * Each {@code ApiDiffGenerator} object computes the list of intersecting and
+ * missing {@link ApiPackageDiffGenerator} objects. Each
+ * {@code ApiPackageDiffGenerator} object in turn computes the list of
+ * intersecting and missing {@link ApiClassDiffGenerator} objects. Each
+ * {@code ApiClassDiffGenerator} object in turn computes the list of
+ * intersecting and missing API members. The members are represented by
+ * {@link ApiConstructor} for constructors, {@link ApiMethod} for methods, and
+ * {@link ApiField} for fields.
+ * </p>
  * 
- * For each intersecting apiMember, a list of ApiChange objects is stored. Each
- * ApiChange object encodes a specific Api change like adding the 'final'
- * keyword to an apiMethod.
+ * <p>
+ * For each intersecting API member, a list of {@link ApiChange} objects is
+ * stored. Each ApiChange object encodes a specific {@code ApiChange} like
+ * adding the 'final' keyword to the API member.
  * 
  */
 public class ApiCompatibilityChecker {
 
+  // TODO(amitmanjhi): use ToolBase for command-line processing
+
+  // TODO(amitmanjhi): check gwt's dev/core/src files. Would need the ability to
+  // build TypeOracle from class files
+
+  // TODO(amitmanjhi): ignore API breakages due to impl package. More generally,
+  // white-list of packages that should not be checked.
+
+  // TODO(amitmanjhi): better handling of exceptions and exception-chaining.
+
+  // currently doing only source_compatibility. true by default.
   public static final boolean API_SOURCE_COMPATIBILITY = true;
-  public static final boolean REMOVE_ABSTRACT_CLASS_FROM_API = true;
-  public static final boolean IGNORE_WHITELIST = false;
-  public static final boolean PRINT_COMPATIBLE_WITH = false;
-  public static final boolean PRINT_INTERSECTIONS = false;
-  public static final boolean REMOVE_DUPLICATES = true;
+
+  // prints which class the member was declared in, false by default
   public static final boolean DEBUG = false;
-  public static final boolean DISABLE_CHECKS = true;
 
-  private static final AbstractTreeLogger logger1 = createTreeLogger();
+  // prints the API of the two containers, false by default.
+  public static final boolean DEBUG_PRINT_ALL_API = false;
 
-  public static String getApiDiff(ApiDiffGenerator temp,
-      HashSet<String> whiteList, boolean removeDuplicates)
-      throws NotFoundException {
-    temp.computeApiDiff();
-    if (removeDuplicates) {
-      temp.cleanApiDiff();
-    }
-    String apiDifferences = temp.printApiDiff();
-    return removeWhiteListMatches(apiDifferences, whiteList);
+  // these two parameters print APIs common in the two repositories. Should be
+  // false by default.
+  public static final boolean PRINT_COMPATIBLE = false;
+
+  public static final boolean PRINT_COMPATIBLE_WITH = false;
+  // for debugging. To see if TypeOracle builds
+  public static final boolean PROCESS_EXISTING_API = true;
+
+  public static final boolean PROCESS_NEW_API = true;
+  // true by default
+  public static final boolean REMOVE_NON_SUBCLASSABLE_ABSTRACT_CLASS_FROM_API =
+      true;
+
+  // Tweak for log output.
+  public static final TreeLogger.Type type = TreeLogger.ERROR;
+
+  // remove duplicates by default
+  public static Collection<ApiChange> getApiDiff(ApiContainer newApi,
+      ApiContainer existingApi, Set<String> whiteList) throws NotFoundException {
+    ApiDiffGenerator apiDiff = new ApiDiffGenerator(newApi, existingApi);
+    return getApiDiff(apiDiff, whiteList, true);
   }
 
   // Call APIBuilders for each of the 2 source trees
@@ -78,100 +116,132 @@
 
     try {
       ApiContainer newApi = null, existingApi = null;
-      boolean processNewApi = true;
-      boolean processExistingApi = true;
 
       if (args.length < 1) {
         printHelp();
         System.exit(-1);
       }
 
-      if (processNewApi) {
-        newApi = new ApiContainer(args[0], "_new", logger1);
-      }
-      if (processExistingApi) {
-        existingApi = new ApiContainer(args[0], "_old", logger1);
-      }
-
-      if ((processNewApi && processExistingApi)
-          && (newApi != null && existingApi != null)) {
-        HashSet<String> whiteList = new HashSet<String>();
-        if (!IGNORE_WHITELIST) {
-          whiteList = readStringFromFile(args[0]);
+      AbstractTreeLogger logger = new PrintWriterTreeLogger();
+      logger.setMaxDetail(type);
+      if (PROCESS_NEW_API) {
+        newApi = new ApiContainer(args[0], "_new", logger);
+        if (ApiCompatibilityChecker.DEBUG_PRINT_ALL_API) {
+          logger.log(TreeLogger.INFO, newApi.getApiAsString()); // print the API
         }
-
-        ApiDiffGenerator apiDiff = new ApiDiffGenerator(newApi, existingApi);
-        String apiDifferences = getApiDiff(apiDiff, whiteList,
-            REMOVE_DUPLICATES);
-        System.out.println(apiDifferences);
-        System.out.println("\t\t\t\tApi Compatibility Checker tool, Copyright Google Inc. 2008");
-        System.exit(apiDifferences.length() == 0 ? 0 : 1);
+      }
+      if (PROCESS_EXISTING_API) {
+        existingApi = new ApiContainer(args[0], "_old", logger);
+        if (ApiCompatibilityChecker.DEBUG_PRINT_ALL_API) {
+          logger.log(TreeLogger.INFO, existingApi.getApiAsString());
+        }
       }
 
+      if (PROCESS_NEW_API && PROCESS_EXISTING_API) {
+        Collection<ApiChange> apiDifferences =
+            getApiDiff(newApi, existingApi, readWhiteListFromFile(args[0]));
+        for (ApiChange apiChange : apiDifferences) {
+          System.out.println(apiChange);
+        }
+        System.out.println("\t\t\t\tApi Compatibility Checker tool, Copyright Google Inc. 2008");
+        System.exit(apiDifferences.size() == 0 ? 0 : 1);
+      }
     } catch (Exception e) {
-      System.err.println("Exception " + e.getMessage()
-          + ", printing stacktrace");
+      // intercepting all exceptions in main, because I have to exit with -1 so
+      // that the build breaks.
       e.printStackTrace();
       System.exit(-1);
     }
   }
 
   public static void printHelp() {
-    System.out.println("java ApiCompatibilityChecker configFile\n");
-    System.out.println("The ApiCompatibilityChecker tool requires a config file as an argument. "
-        + "The config file must specify two repositories of java source files "
-        + "that must be compared for API source compatibility. Each repository "
-        + "must specify three properties: 'name', 'sourceFiles', and 'excludeFiles.' "
-        + "A suffix of '_old' is attached to properties of the first repository, "
-        + "while a suffix of '_new' is attached to properties of the second "
-        + "repository. An optional whitelist can also be present at the end of "
-        + "the config file. The format of the whitelist is same as the output of "
-        + "the tool without the whitelist.");
-    System.out.println();
-    System.out.println("The name property specifies the api name that should "
-        + "be used in the output. The sourceFiles property, a colon-separated "
-        + "list of files/directories, specifies the roots of the the filesystem "
-        + "trees that must be included. The excludeFiles property, "
-        + "a colon-separated lists of files/directories specifies the roots of "
-        + "the filesystem trees that must be excluded.");
-    System.out.println();
-    System.out.println();
-    System.out.println("Example api.conf file:\n"
+    StringBuffer sb = new StringBuffer();
+    sb.append("java ApiCompatibilityChecker configFile\n");
+    sb.append("The ApiCompatibilityChecker tool requires a config file as an argument. ");
+    sb.append("The config file must specify two repositories of java source files: ");
+    sb.append("'_old' and '_new', which are to be compared for API source compatibility.\n");
+    sb.append("An optional whitelist is present at the end of ");
+    sb.append("the config file. The format of the whitelist is same as the output of ");
+    sb.append("the tool without the whitelist.\n");
+    sb.append("Each repository is specified by the following four properties:\n");
+    sb.append("name           specifies how the api should be refered to in the output\n");
+    sb.append("dirRoot        optional argument that specifies the base directory of all other file/directory names\n");
+    sb.append("sourceFiles    a colon-separated list of files/directories that specify the roots of the the filesystem trees to be included.\n");
+    sb.append("excludeFiles   a colon-separated lists of files/directories that specify the roots of the filesystem trees to be excluded");
 
-        + "name_old gwtEmulator\n"
-        + "sourceFiles_old dev/core/super/com/google/gwt/dev/jjs/intrinsic/:user/super/com/google/gwt/emul/:user/src/com/google/gwt/core/client\n"
-        + "excludeFiles_old \n\n"
+    sb.append("\n\n");
+    sb.append("Example api.conf file:\n");
+    sb.append("name_old         gwtEmulator");
+    sb.append("\n");
+    sb.append("dirRoot_old      ./");
+    sb.append("\n");
+    sb.append("sourceFiles_old  dev/core/super:user/super:user/src");
+    sb.append("\n");
+    sb.append("excludeFiles_old user/super/com/google/gwt/junit");
+    sb.append("\n\n");
 
-        + "name_new gwtEmulatorCopy\n"
-        + "sourceFiles_new dev/core/super/com/google/gwt/dev/jjs/intrinsic/:user/super/com/google/gwt/emul/:user/src/com/google/gwt/core/client\n"
-        + "excludeFiles_new \n\n");
+    sb.append("name_new         gwtEmulatorCopy");
+    sb.append("\n");
+    sb.append("dirRoot_new      ../gwt-14/");
+    sb.append("\n");
+    sb.append("sourceFiles_new  dev/core:user/super:user/src");
+    sb.append("\n");
+    sb.append("excludeFiles_new user/super/com/google/gwt/junit");
+    sb.append("\n\n");
+
+    System.out.println(sb.toString());
+  }
+
+  // interface for testing, since do not want to build ApiDiff frequently
+  static Collection<ApiChange> getApiDiff(ApiDiffGenerator apiDiff,
+      Set<String> whiteList, boolean removeDuplicates) throws NotFoundException {
+    Collection<ApiChange> collection = apiDiff.getApiDiff(removeDuplicates);
+    Set<ApiChange> prunedCollection = new HashSet<ApiChange>();
+    for (ApiChange apiChange : collection) {
+      String apiChangeAsString = apiChange.toString();
+      apiChangeAsString = apiChangeAsString.trim();
+      if (whiteList.remove(apiChangeAsString)) {
+        continue;
+      }
+      // check for Status.Compatible and Status.Compatible_with
+      if (!PRINT_COMPATIBLE
+          && apiChange.getStatus().equals(ApiChange.Status.COMPATIBLE)) {
+        continue;
+      }
+      if (!PRINT_COMPATIBLE_WITH
+          && apiChange.getStatus().equals(ApiChange.Status.COMPATIBLE_WITH)) {
+        continue;
+      }
+      prunedCollection.add(apiChange);
+    }
+    if (whiteList.size() > 0) {
+      List<String> al = new ArrayList<String>(whiteList);
+      Collections.sort(al);
+      System.err.println("ApiChanges "
+          + al
+          + ",  not found. Are you using a properly formatted configuration file?");
+    }
+    List<ApiChange> apiChangeList = new ArrayList<ApiChange>(prunedCollection);
+    Collections.sort(apiChangeList);
+    return apiChangeList;
   }
 
   /**
-   * Tweak this for the log output.
+   * Each whiteList element is an {@link ApiElement} and
+   * {@link ApiChange.Status} separated by space. For example,
+   * "java.util.ArrayList::size() MISSING". The {@code ApiElement} is
+   * represented as the string obtained by invoking the getRelativeSignature()
+   * method on {@link ApiElement}.
+   * 
+   * @param fileName
+   * @return
    */
-  private static AbstractTreeLogger createTreeLogger() {
-    AbstractTreeLogger logger = new PrintWriterTreeLogger();
-    int choice = 3; // 1, 2, 3
-    switch (choice) {
-      case 1:
-        logger.setMaxDetail(TreeLogger.ALL);
-        break;
-      case 2:
-        logger.setMaxDetail(null);
-        break;
-      default:
-        logger.setMaxDetail(TreeLogger.ERROR);
-    }
-    return logger;
-  }
-
-  private static HashSet<String> readStringFromFile(String fileName)
+  private static Set<String> readWhiteListFromFile(String fileName)
       throws IOException {
     if (fileName == null) {
       throw new IllegalArgumentException("fileName is null");
     }
-    HashSet<String> hashSet = new HashSet<String>();
+    Set<String> hashSet = new HashSet<String>();
     FileReader fr = new FileReader(fileName);
     BufferedReader br = new BufferedReader(fr);
     String str = null;
@@ -182,34 +252,12 @@
         continue;
       }
       String splits[] = str.split(" ");
-      if (splits.length > 1) {
-        hashSet.add(splits[0] + " " + splits[1]);
+      if (splits.length > 1 && ApiChange.contains(splits[1])) {
+        String identifier = splits[0] + ApiDiffGenerator.DELIMITER + splits[1];
+        hashSet.add(identifier.trim());
       }
     }
     return hashSet;
   }
 
-  private static String removeWhiteListMatches(String apiDifferences,
-      HashSet<String> whiteList) {
-    String apiDifferencesArray[] = apiDifferences.split("\n");
-    String whiteListArray[] = whiteList.toArray(new String[0]);
-    for (int i = 0; i < apiDifferencesArray.length; i++) {
-      String temp = apiDifferencesArray[i].trim();
-      for (String whiteListElement : whiteListArray) {
-        if (temp.startsWith(whiteListElement)) {
-          apiDifferencesArray[i] = "";
-        }
-      }
-    }
-
-    StringBuffer sb = new StringBuffer();
-    for (String temp : apiDifferencesArray) {
-      if (temp.length() > 0) {
-        sb.append(temp);
-        sb.append("\n");
-      }
-    }
-    return sb.toString();
-  }
-
-}
+}
\ No newline at end of file
diff --git a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiConstructor.java b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiConstructor.java
index fd57b57..8390145 100644
--- a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiConstructor.java
+++ b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiConstructor.java
@@ -17,26 +17,28 @@
 
 import com.google.gwt.core.ext.typeinfo.JAbstractMethod;
 
-import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
 
 /**
  * Encapsulates an API constructor.
  */
-public class ApiConstructor extends ApiAbstractMethod {
+final class ApiConstructor extends ApiAbstractMethod {
 
-  public ApiConstructor(JAbstractMethod method, ApiClass apiClass) {
+  ApiConstructor(JAbstractMethod method, ApiClass apiClass) {
     super(method, apiClass);
   }
 
   @Override
-  public ApiChange checkReturnTypeCompatibility(ApiAbstractMethod newMethod) {
+  ApiChange checkReturnTypeCompatibility(ApiAbstractMethod newMethod) {
     return null;
   }
 
+  /**
+   * returns an immutable List.
+   */
   @Override
-  public ArrayList<ApiChange.Status> getModifierChanges(
-      ApiAbstractMethod newMethod) {
-    return new ArrayList<ApiChange.Status>(0);
+  List<ApiChange.Status> getModifierChanges(ApiAbstractMethod newMethod) {
+    return Collections.emptyList();
   }
-
 }
\ No newline at end of file
diff --git a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiContainer.java b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiContainer.java
index 2a89cb9..47c8112 100644
--- a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiContainer.java
+++ b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiContainer.java
@@ -18,6 +18,8 @@
 
 import com.google.gwt.core.ext.TreeLogger;
 import com.google.gwt.core.ext.UnableToCompleteException;
+import com.google.gwt.core.ext.typeinfo.JClassType;
+import com.google.gwt.core.ext.typeinfo.JConstructor;
 import com.google.gwt.core.ext.typeinfo.JPackage;
 import com.google.gwt.core.ext.typeinfo.NotFoundException;
 import com.google.gwt.core.ext.typeinfo.TypeOracle;
@@ -33,75 +35,119 @@
 import java.io.FileReader;
 import java.io.IOException;
 import java.net.MalformedURLException;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
-import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
 import java.util.Properties;
 import java.util.Set;
 import java.util.Vector;
 
 /**
- * Encapsulates an API.
+ * {@link ApiContainer} Encapsulates an API.
  * 
  */
-public class ApiContainer {
+public final class ApiContainer {
 
-  private HashMap<String, ApiPackage> apiPackages = new HashMap<String, ApiPackage>();
-  private HashMap<String, String> excludedFiles = null;
+  private Map<JClassType, Boolean> apiClassCache =
+      new HashMap<JClassType, Boolean>();
+  private Map<String, ApiPackage> apiPackages =
+      new HashMap<String, ApiPackage>();
+
+  private Map<String, String> excludedFiles = null;
   private TreeLogger logger = null;
+
   private String name = null;
+
   private int numFilesCount = 0;
   private Collection<File> sourceTrees = null;
   private TypeOracle typeOracle = null;
 
+  /**
+   * A public constructor to create an {@code ApiContainer} from a config file.
+   * 
+   * @param fileName the config file
+   * @param suffix The code looks for the values of the properties: dirRoot,
+   *          name, sourceFiles, excludedFiles, ending in "suffix"
+   * @param logger The logger for the code.
+   * @throws IllegalArgumentException if one of the arguments is illegal
+   * @throws UnableToCompleteException if there is a TypeOracle exception
+   */
   public ApiContainer(String fileName, String suffix, TreeLogger logger)
-      throws IllegalArgumentException, MalformedURLException,
-      FileNotFoundException, IOException, NotFoundException,
-      UnableToCompleteException {
+      throws IllegalArgumentException, UnableToCompleteException {
     this.logger = logger;
     if (fileName == null) {
       throw new IllegalArgumentException("fileName is null");
     }
-    FileInputStream fis = new FileInputStream(fileName);
-    Properties config = new Properties();
-    config.load(fis);
-    String apiName = config.getProperty("name" + suffix);
-    String allSourceFiles = config.getProperty("sourceFiles" + suffix);
-    String allExcludedFiles = config.getProperty("excludedFiles" + suffix);
+    try {
+      FileInputStream fis = new FileInputStream(fileName);
+      Properties config = new Properties();
+      config.load(fis);
+      String apiName = config.getProperty("name" + suffix);
+      String allSourceFiles = config.getProperty("sourceFiles" + suffix);
+      String allExcludedFiles = config.getProperty("excludedFiles" + suffix);
 
-    if (allExcludedFiles == null) {
-      allExcludedFiles = "";
-    }
-    if (apiName == null || allSourceFiles == null) {
-      throw new IllegalArgumentException(
-          "in apiContainer constructor, either name (" + apiName
-              + ") or sourceFiles (" + allSourceFiles + ") is null");
-    }
-    logger.log(TreeLogger.DEBUG, "read from config file " + fileName
-        + ", name = " + apiName + ", allSourceFiles = " + allSourceFiles
-        + ", allExcludedFiles = " + allExcludedFiles, null);
+      if (allExcludedFiles == null) {
+        allExcludedFiles = "";
+      }
+      if (apiName == null || allSourceFiles == null) {
+        throw new IllegalArgumentException(
+            "in apiContainer constructor, either name (" + apiName
+                + ") or sourceFiles (" + allSourceFiles + ") is null");
+      }
+      logger.log(TreeLogger.DEBUG, "read from config file " + fileName
+          + ", name = " + apiName + ", allSourceFiles = " + allSourceFiles
+          + ", allExcludedFiles = " + allExcludedFiles, null);
 
-    String sourceFilesArray[] = allSourceFiles.split(":");
-    Collection<File> fileCollection = new Vector<File>();
-    for (String tempStr : sourceFilesArray) {
-      tempStr = tempStr.trim();
-      fileCollection.add(new File(tempStr));
+      String dirRoot = config.getProperty("dirRoot" + suffix);
+      if (dirRoot == null) {
+        dirRoot = "";
+      }
+      String sourceFilesArray[] = allSourceFiles.split(":");
+      Collection<File> fileCollection = new Vector<File>();
+      for (String tempStr : sourceFilesArray) {
+        tempStr = tempStr.trim();
+        checkFileExistence("source file: ", dirRoot + tempStr);
+        fileCollection.add(new File(dirRoot + tempStr));
+      }
+      logger.log(TreeLogger.DEBUG, "fileCollection " + fileCollection, null);
+      this.sourceTrees = fileCollection;
+      if (allExcludedFiles.equals("")) {
+        this.excludedFiles = generateCanonicalHashmap(new String[0], dirRoot);
+      } else {
+        String excludedFilesArray[] = allExcludedFiles.split(":");
+        for (String excludedFile : excludedFilesArray) {
+          checkFileExistence("excluded file: ", dirRoot + excludedFile);
+        }
+        this.excludedFiles =
+            generateCanonicalHashmap(excludedFilesArray, dirRoot);
+      }
+      this.name = apiName;
+      createTypeOracleFromSources();
+      initializeApiPackages();
+    } catch (MalformedURLException e1) {
+      throw new IllegalArgumentException(e1);
+    } catch (FileNotFoundException e2) {
+      throw new IllegalArgumentException(e2);
+    } catch (IOException e3) {
+      throw new IllegalArgumentException(e3);
+    } catch (NotFoundException e4) {
+      logger.log(TreeLogger.ERROR, "logged a NotFoundException", e4);
+      throw new UnableToCompleteException();
     }
-    this.sourceTrees = fileCollection;
-    if (allExcludedFiles.equals("")) {
-      this.excludedFiles = generateCanonicalHashmap(new String[0]);
-    } else {
-      String excludedFilesArray[] = allExcludedFiles.split(":");
-      this.excludedFiles = generateCanonicalHashmap(excludedFilesArray);
-    }
-    this.name = apiName;
-    createTypeOracleFromSources();
-    initializeApiPackages();
   }
 
-  // constructor is used while testing
+  /**
+   * Another public constructor. Used for programmatic invocation and testing.
+   * 
+   * @param name
+   * @param logger
+   * @param typeOracle
+   */
   ApiContainer(String name, TreeLogger logger, TypeOracle typeOracle) {
     this.name = name;
     this.logger = logger;
@@ -109,21 +155,83 @@
     initializeApiPackages();
   }
 
-  public ApiPackage getApiPackage(String packageName) {
+  /**
+   * Get all the API members as String.
+   * 
+   * @return the string value
+   */
+  public String getApiAsString() {
+    StringBuffer sb = new StringBuffer();
+    sb.append("Api: " + name + "\n\n");
+    List<ApiPackage> sortedApiPackages =
+        new ArrayList<ApiPackage>(apiPackages.values());
+    Collections.sort(sortedApiPackages);
+    for (ApiPackage apiPackage : apiPackages.values()) {
+      sb.append(apiPackage.getApiAsString());
+    }
+    return sb.toString();
+  }
+
+  ApiPackage getApiPackage(String packageName) {
     return apiPackages.get(packageName);
   }
 
-  public HashSet<String> getApiPackageNames() {
+  HashSet<String> getApiPackageNames() {
     return new HashSet<String>(apiPackages.keySet());
   }
 
-  public TreeLogger getLogger() {
+  Set<ApiPackage> getApiPackagesBySet(Set<String> names) {
+    Set<ApiPackage> ret = new HashSet<ApiPackage>();
+    for (String packageName : names) {
+      ret.add(apiPackages.get(packageName));
+    }
+    return ret;
+  }
+
+  TreeLogger getLogger() {
     return logger;
   }
 
+  boolean isApiClass(JClassType classType) {
+    Boolean ret = apiClassCache.get(classType);
+    if (ret != null) {
+      return ret.booleanValue();
+    }
+    // to avoid infinite recursion for isApiClass("BAR", ..) when:
+    // class FOO {
+    // public class BAR extends FOO {
+    // }
+    // }
+    apiClassCache.put(classType, Boolean.FALSE);
+    boolean bool = computeIsApiClass(classType);
+    if (bool) {
+      apiClassCache.put(classType, Boolean.TRUE);
+    } else {
+      apiClassCache.put(classType, Boolean.FALSE);
+    }
+    // container.getLogger().log(TreeLogger.SPAM, "computed isApiClass for " +
+    // classType + " as " + bool, null);
+    return bool;
+  }
+
+  boolean isInstantiableApiClass(JClassType classType) {
+    return !classType.isAbstract() && isApiClass(classType)
+        && hasPublicOrProtectedConstructor(classType);
+  }
+
+  boolean isNotsubclassableApiClass(JClassType classType) {
+    return isApiClass(classType) && !isSubclassable(classType);
+  }
+
+  boolean isSubclassableApiClass(JClassType classType) {
+    return isApiClass(classType) && isSubclassable(classType);
+  }
+
   private void addCompilationUnitsInPath(Set<CompilationUnit> units,
       File sourcePathEntry) throws NotFoundException, IOException,
       UnableToCompleteException {
+    logger.log(TreeLogger.SPAM, "entering addCompilationUnitsInPath, file = "
+        + sourcePathEntry, null);
     File[] files = sourcePathEntry.listFiles();
     if (files == null) {
       // No files found.
@@ -132,6 +240,7 @@
 
     for (int i = 0; i < files.length; i++) {
       final File file = files[i];
+      logger.log(TreeLogger.SPAM, "deciding the fate of file " + file, null);
       // Ignore files like .svn and .cvs
       if (file.getName().startsWith(".") || file.getName().equals("CVS")) {
         continue;
@@ -146,8 +255,8 @@
         String pkgName = null;
         if (file.getName().endsWith("java")) {
           pkgName = extractPackageNameFromFile(file);
-          logger.log(TreeLogger.DEBUG, "pkgName = " + pkgName + ", file = "
-              + file.toString(), null);
+          logger.log(TreeLogger.DEBUG, "adding pkgName = " + pkgName
+              + ", file = " + file.toString(), null);
         }
         if (isValidPackage(pkgName, sourcePathEntry.toURL().toString())) {
           // Add if it's a source file and the package and fileNames are okay
@@ -164,14 +273,48 @@
     }
   }
 
+  private void checkFileExistence(String tag, String pathName)
+      throws FileNotFoundException {
+    File tempFile = new File(pathName);
+    if (!tempFile.exists()) {
+      throw new FileNotFoundException(tag + "file " + pathName + " not found");
+    }
+  }
+
+  /**
+   * Assumption: Clients may subclass an API class, but they will not add their
+   * class to the package.
+   * 
+   * Notes: -- A class with only private constructors can be an API class.
+   */
+  private boolean computeIsApiClass(JClassType classType) {
+    // check for outer classes
+    if (isPublicOuterClass(classType)) {
+      return true;
+    }
+    // if classType is not a member type, return false
+    if (!classType.isMemberType()) {
+      return false;
+    }
+    JClassType enclosingType = classType.getEnclosingType();
+    if (classType.isPublic()) {
+      return isApiClass(enclosingType) || isAnySubtypeAnApiClass(enclosingType);
+    }
+    if (classType.isProtected()) {
+      return isSubclassableApiClass(enclosingType)
+          || isAnySubtypeASubclassableApiClass(enclosingType);
+    }
+    return false;
+  }
+
   private void createTypeOracleFromSources() throws NotFoundException,
       IOException, UnableToCompleteException {
 
     numFilesCount = 0;
     TypeOracleMediator mediator = new TypeOracleMediator();
     Set<CompilationUnit> units = new HashSet<CompilationUnit>();
-    for (Iterator<File> i = sourceTrees.iterator(); i.hasNext();) {
-      addCompilationUnitsInPath(units, i.next());
+    for (File tempFile : sourceTrees) {
+      addCompilationUnitsInPath(units, tempFile);
     }
     JdtCompiler.compile(units);
     mediator.refresh(logger, units);
@@ -212,32 +355,40 @@
   /**
    * Convert a set into a HashMap for faster lookups.
    */
-  private HashMap<String, String> generateCanonicalHashmap(String strArray[])
-      throws IOException {
+  private HashMap<String, String> generateCanonicalHashmap(String strArray[],
+      String dirRoot) throws IOException {
     HashMap<String, String> tempMap = new HashMap<String, String>();
     if (strArray == null) {
       return tempMap;
     }
     for (String str : strArray) {
       str = str.trim();
-      File tempFile = new File(str);
+      File tempFile = new File(dirRoot + str);
       str = tempFile.getCanonicalPath();
       tempMap.put(str, str);
     }
     return tempMap;
   }
 
+  private boolean hasPublicOrProtectedConstructor(JClassType classType) {
+    JConstructor[] constructors = classType.getConstructors();
+    for (JConstructor constructor : constructors) {
+      if (constructor.isPublic() || constructor.isProtected()) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   /**
    * Purge non API packages.
    */
   private void initializeApiPackages() {
-    HashSet<JPackage> allPackages = new HashSet<JPackage>(
-        Arrays.asList(typeOracle.getPackages()));
-    Iterator<JPackage> packagesIterator = allPackages.iterator();
-    HashSet<String> packagesNotAdded = new HashSet<String>();
-    while (packagesIterator.hasNext()) {
-      JPackage packageObject = packagesIterator.next();
-      if (ApiPackage.isApiPackage(packageObject)) {
+    Set<JPackage> allPackages =
+        new HashSet<JPackage>(Arrays.asList(typeOracle.getPackages()));
+    Set<String> packagesNotAdded = new HashSet<String>();
+    for (JPackage packageObject : allPackages) {
+      if (isApiPackage(packageObject)) {
         ApiPackage apiPackageObj = new ApiPackage(packageObject, this);
         apiPackages.put(apiPackageObj.getName(), apiPackageObj);
       } else {
@@ -249,11 +400,49 @@
           + packagesNotAdded.size() + " packages: " + packagesNotAdded, null);
     }
     if (apiPackages.size() > 0) {
-      logger.log(TreeLogger.INFO, "API " + name + apiPackages.size()
+      logger.log(TreeLogger.INFO, "API " + name + " " + apiPackages.size()
           + " Api packages: " + apiPackages.keySet(), null);
     }
   }
 
+  private boolean isAnySubtypeAnApiClass(JClassType classType) {
+    JClassType subTypes[] = classType.getSubtypes();
+    for (JClassType tempType : subTypes) {
+      if (isApiClass(tempType)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  private boolean isAnySubtypeASubclassableApiClass(JClassType classType) {
+    JClassType subTypes[] = classType.getSubtypes();
+    for (JClassType tempType : subTypes) {
+      if (isSubclassableApiClass(tempType)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  /**
+   * A package is an API package if it contains at least one API class. Refer
+   * http://wiki.eclipse.org/index.php/Evolving_Java-based_APIs This definition
+   * boils down to "a package is an API package iff it contains at least one API
+   * class that is not enclosed in any other class."
+   * 
+   * @return return true if and only if the packageObject is an apiPackage
+   */
+  private boolean isApiPackage(JPackage packageObject) {
+    JClassType classTypes[] = packageObject.getTypes();
+    for (JClassType classType : classTypes) {
+      if (isPublicOuterClass(classType)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   private boolean isExcludedFile(String fileName) {
     String pattern = "file:";
     if (fileName.indexOf(pattern) == 0) {
@@ -262,6 +451,17 @@
     return (excludedFiles.get(fileName) != null);
   }
 
+  /**
+   * @return returns true if classType is public AND an outer class
+   */
+  private boolean isPublicOuterClass(JClassType classType) {
+    return classType.isPublic() && !classType.isMemberType();
+  }
+
+  private boolean isSubclassable(JClassType classType) {
+    return !classType.isFinal() && hasPublicOrProtectedConstructor(classType);
+  }
+
   private boolean isValidPackage(String packageName, String filePath) {
     logger.log(TreeLogger.SPAM, "packageName = " + packageName
         + ", filePath = " + filePath, null);
diff --git a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiDiffGenerator.java b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiDiffGenerator.java
index d108370..0593887 100644
--- a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiDiffGenerator.java
+++ b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiDiffGenerator.java
@@ -21,32 +21,25 @@
 import com.google.gwt.core.ext.typeinfo.NotFoundException;
 import com.google.gwt.core.ext.typeinfo.TypeOracle;
 
+import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
-import java.util.Iterator;
+import java.util.Map;
+import java.util.Set;
 
 /**
- * encapsulates a class that produces the diff between two api's.
+ * {@link ApiDiffGenerator} encapsulates a class that produces the diff between
+ * two api's.
  */
-public class ApiDiffGenerator {
+public final class ApiDiffGenerator {
 
   public static final String DELIMITER = " ";
 
-  @SuppressWarnings("unchecked")
-  public static HashSet<String> extractCommonElements(HashSet<String> s1,
-      HashSet<String> s2) {
-    HashSet<String> intersection = (HashSet<String>) s1.clone();
-    intersection.retainAll(s2);
-    s1.removeAll(intersection);
-    s2.removeAll(intersection);
-    return intersection;
-  }
-
   /**
    * The two types might belong to different typeOracles.
    */
-  public static boolean isFirstTypeAssignableToSecond(JType firstType,
-      JType secondType) {
+  static boolean isFirstTypeAssignableToSecond(JType firstType, JType secondType) {
 
     // getJNISignature() does TypeErasure
     if (firstType.getJNISignature().equals(secondType.getJNISignature())) {
@@ -59,8 +52,10 @@
     }
     TypeOracle newApiTypeOracle = classType2.getOracle();
     // get the appropriate classObject in the newApi
-    JClassType firstClassType = newApiTypeOracle.findType(classType1.getQualifiedSourceName());
-    JClassType secondClassType = newApiTypeOracle.findType(classType2.getQualifiedSourceName());
+    JClassType firstClassType =
+        newApiTypeOracle.findType(classType1.getQualifiedSourceName());
+    JClassType secondClassType =
+        newApiTypeOracle.findType(classType2.getQualifiedSourceName());
     // The types might not necessarily exist in the newApi
     if (firstClassType == null || secondClassType == null) {
       return false;
@@ -68,49 +63,45 @@
     return firstClassType.isAssignableTo(secondClassType);
   }
 
-  HashMap<String, ApiPackageDiffGenerator> intersectingPackages = new HashMap<String, ApiPackageDiffGenerator>();
+  @SuppressWarnings("unchecked")
+  static Set<String> removeIntersection(Set<String> s1, Set<String> s2) {
+    Set<String> intersection = new HashSet<String>(s1);
+    intersection.retainAll(s2);
+    s1.removeAll(intersection);
+    s2.removeAll(intersection);
+    return intersection;
+  }
 
-  HashSet<String> missingPackageNames = null;
-  ApiContainer newApi = null;
-
-  ApiContainer oldApi = null;
+  Map<String, ApiPackageDiffGenerator> intersectingPackages =
+      new HashMap<String, ApiPackageDiffGenerator>();
+  Set<String> missingPackageNames;
+  final ApiContainer newApi;
+  final ApiContainer oldApi;
 
   ApiDiffGenerator(ApiContainer newApi, ApiContainer oldApi) {
     this.newApi = newApi;
     this.oldApi = oldApi;
   }
 
-  public void cleanApiDiff() {
-    Iterator<ApiPackageDiffGenerator> tempIterator = intersectingPackages.values().iterator();
-    while (tempIterator.hasNext()) {
-      tempIterator.next().cleanApiDiff();
+  Collection<ApiChange> getApiDiff(boolean removeDuplicates)
+      throws NotFoundException {
+    computeApiDiff();
+    if (removeDuplicates) {
+      cleanApiDiff();
     }
+    Collection<ApiChange> collection = new ArrayList<ApiChange>();
+    Set<ApiPackage> missingPackages =
+        oldApi.getApiPackagesBySet(missingPackageNames);
+    for (ApiPackage missingPackage : missingPackages) {
+      collection.add(new ApiChange(missingPackage, ApiChange.Status.MISSING));
+    }
+    for (ApiPackageDiffGenerator intersectingPackage : intersectingPackages.values()) {
+      collection.addAll(intersectingPackage.getApiDiff());
+    }
+    return collection;
   }
 
-  /**
-   * Compares 2 APIs for source compatibility. Algorithm: First find packages
-   * that are in one but not in another. Then, look at at classes in the common
-   * packages. Look at public classes.
-   * 
-   */
-  public void computeApiDiff() throws NotFoundException {
-    HashSet<String> newApiPackageNames = newApi.getApiPackageNames();
-    missingPackageNames = oldApi.getApiPackageNames();
-    HashSet<String> intersection = extractCommonElements(newApiPackageNames,
-        missingPackageNames);
-    // Inspect each of the classes in each of the packages in the intersection
-    Iterator<String> tempIterator = intersection.iterator();
-    while (tempIterator.hasNext()) {
-      String packageName = tempIterator.next();
-      ApiPackageDiffGenerator temp = new ApiPackageDiffGenerator(packageName,
-          this);
-      intersectingPackages.put(packageName, temp);
-      temp.computeApiDiff();
-    }
-  }
-
-  public ApiClassDiffGenerator findApiClassDiffGenerator(JClassType classType) {
-    String className = classType.getQualifiedSourceName();
+  ApiClassDiffGenerator findApiClassDiffGenerator(String className) {
     int i = className.length() - 1;
     while (i >= 0) {
       int dot = className.lastIndexOf('.', i);
@@ -123,8 +114,8 @@
       } else {
         i = -1;
       }
-      ApiClassDiffGenerator result = findApiClassDiffGenerator(pkgName,
-          typeName);
+      ApiClassDiffGenerator result =
+          findApiClassDiffGenerator(pkgName, typeName);
       if (result != null) {
         return result;
       }
@@ -140,12 +131,12 @@
    * 
    * @return <code>null</code> if the type is not found
    */
-  public ApiClassDiffGenerator findApiClassDiffGenerator(String pkgName,
+  ApiClassDiffGenerator findApiClassDiffGenerator(String pkgName,
       String typeName) {
     ApiPackageDiffGenerator pkg = findApiPackageDiffGenerator(pkgName);
     if (pkg != null) {
-      ApiClassDiffGenerator type = pkg.findApiClassDiffGenerator(pkgName + "."
-          + typeName);
+      ApiClassDiffGenerator type =
+          pkg.findApiClassDiffGenerator(pkgName + "." + typeName);
       if (type != null) {
         return type;
       }
@@ -153,30 +144,42 @@
     return null;
   }
 
-  public ApiPackageDiffGenerator findApiPackageDiffGenerator(String key) {
+  ApiPackageDiffGenerator findApiPackageDiffGenerator(String key) {
     return intersectingPackages.get(key);
   }
 
-  public ApiContainer getNewApiContainer() {
+  ApiContainer getNewApiContainer() {
     return newApi;
   }
 
-  public ApiContainer getOldApiContainer() {
+  ApiContainer getOldApiContainer() {
     return oldApi;
   }
 
-  public String printApiDiff() {
-    StringBuffer sb = new StringBuffer();
-    Iterator<String> missingPackagesIterator = missingPackageNames.iterator();
-    while (missingPackagesIterator.hasNext()) {
-      sb.append(missingPackagesIterator.next() + DELIMITER
-          + ApiChange.Status.MISSING + "\n");
+  private void cleanApiDiff() {
+    for (ApiPackageDiffGenerator intersectingPackage : intersectingPackages.values()) {
+      intersectingPackage.cleanApiDiff();
     }
-    Iterator<ApiPackageDiffGenerator> tempIterator = intersectingPackages.values().iterator();
-    while (tempIterator.hasNext()) {
-      sb.append(tempIterator.next().printApiDiff());
+  }
+
+  /**
+   * Compares 2 APIs for source compatibility. Algorithm: First find packages
+   * that are in one but not in another. Then, look at at classes in the common
+   * packages. Look at public classes.
+   * 
+   */
+  private void computeApiDiff() throws NotFoundException {
+    Set<String> newApiPackageNames = newApi.getApiPackageNames();
+    missingPackageNames = oldApi.getApiPackageNames();
+    Set<String> intersection =
+        removeIntersection(newApiPackageNames, missingPackageNames);
+    // Inspect each of the classes in each of the packages in the intersection
+    for (String packageName : intersection) {
+      ApiPackageDiffGenerator tempPackageDiffGenerator =
+          new ApiPackageDiffGenerator(packageName, this);
+      intersectingPackages.put(packageName, tempPackageDiffGenerator);
+      tempPackageDiffGenerator.computeApiDiff();
     }
-    return sb.toString();
   }
 
 }
diff --git a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiElement.java b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiElement.java
new file mode 100644
index 0000000..c7654b1
--- /dev/null
+++ b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiElement.java
@@ -0,0 +1,23 @@
+/*
+ * Copyright 2008 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.google.gwt.tools.apichecker;
+
+/**
+ * An interface encapsulating any API elements.
+ */
+public interface ApiElement {
+  String getRelativeSignature();
+}
\ No newline at end of file
diff --git a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiField.java b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiField.java
new file mode 100644
index 0000000..9884ebc
--- /dev/null
+++ b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiField.java
@@ -0,0 +1,120 @@
+/*
+ * Copyright 2008 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.google.gwt.tools.apichecker;
+
+import com.google.gwt.core.ext.typeinfo.JClassType;
+import com.google.gwt.core.ext.typeinfo.JField;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * Immutable class that encapsulates an API Field. Useful for set-operations.
+ */
+final class ApiField implements Comparable<ApiField>, ApiElement {
+
+  static String computeApiSignature(JField tempField) {
+    return tempField.getEnclosingType().getQualifiedSourceName() + "::"
+        + tempField.getName();
+  }
+
+  private final ApiClass apiClass;
+  private volatile String apiSignature = null; // cached, lazily initialized
+  private final JField field;
+  private volatile String relativeSignature = null; // cached, lazily
+
+  // initialized
+
+  ApiField(JField field, ApiClass apiClass) {
+    this.field = field;
+    this.apiClass = apiClass;
+  }
+
+  public int compareTo(ApiField other) {
+    return getRelativeSignature().compareTo(other.getRelativeSignature());
+  }
+
+  /**
+   * Used during set operations.
+   */
+  @Override
+  public boolean equals(Object o) {
+    if (o instanceof ApiField) {
+      ApiField other = (ApiField) o;
+      return getApiSignature().equals(other.getApiSignature());
+    }
+    return false;
+  }
+
+  public String getRelativeSignature() {
+    if (relativeSignature == null) {
+      relativeSignature = computeRelativeSignature();
+    }
+    return relativeSignature;
+  }
+
+  @Override
+  public int hashCode() {
+    return getApiSignature().hashCode();
+  }
+
+  @Override
+  public String toString() {
+    return field.toString();
+  }
+
+  String getApiSignature() {
+    if (apiSignature == null) {
+      apiSignature = computeApiSignature();
+    }
+    return apiSignature;
+  }
+
+  JField getField() {
+    return field;
+  }
+
+  Set<ApiChange.Status> getModifierChanges(ApiField newField) {
+    Set<ApiChange.Status> statuses = new HashSet<ApiChange.Status>();
+    if (!field.isFinal() && newField.getField().isFinal()) {
+      statuses.add(ApiChange.Status.FINAL_ADDED);
+    }
+    if ((field.isStatic() && !newField.getField().isStatic())) {
+      statuses.add(ApiChange.Status.STATIC_REMOVED);
+    }
+    return statuses;
+  }
+
+  private String computeApiSignature() {
+    return computeApiSignature(field);
+  }
+
+  private String computeRelativeSignature() {
+    String signature = field.getName();
+    if (ApiCompatibilityChecker.DEBUG) {
+      JClassType enclosingType = field.getEnclosingType();
+      return apiClass.getClassObject().getQualifiedSourceName()
+          + "::"
+          + signature
+          + " defined in "
+          + (enclosingType == null ? "null enclosing type "
+              : enclosingType.getQualifiedSourceName());
+    }
+    return apiClass.getClassObject().getQualifiedSourceName() + "::"
+        + signature;
+  }
+
+}
\ No newline at end of file
diff --git a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiMethod.java b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiMethod.java
index 677099f..c3df50e 100644
--- a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiMethod.java
+++ b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiMethod.java
@@ -20,36 +20,36 @@
 import com.google.gwt.core.ext.typeinfo.JType;
 
 import java.util.ArrayList;
+import java.util.List;
 
 /**
- * Encapsulates an API method.
+ * Encapsulates an API method. Useful for set-operations.
  */
-public class ApiMethod extends ApiAbstractMethod {
+final class ApiMethod extends ApiAbstractMethod {
 
-  public ApiMethod(JAbstractMethod method, ApiClass apiClass) {
+  ApiMethod(JAbstractMethod method, ApiClass apiClass) {
     super(method, apiClass);
   }
 
   @Override
-  public ApiChange checkReturnTypeCompatibility(ApiAbstractMethod newMethod)
+  ApiChange checkReturnTypeCompatibility(ApiAbstractMethod newMethod)
       throws TypeNotPresentException {
     JType firstType, secondType;
-    if (newMethod.getMethodObject() instanceof JMethod
-        && method instanceof JMethod) {
+    if (newMethod.getMethod() instanceof JMethod && method instanceof JMethod) {
       firstType = ((JMethod) method).getReturnType();
-      secondType = ((JMethod) newMethod.getMethodObject()).getReturnType();
+      secondType = ((JMethod) newMethod.getMethod()).getReturnType();
     } else {
       throw new AssertionError("Different types for method = "
           + method.getClass() + ", and newMethodObject = "
-          + newMethod.getMethodObject().getClass() + ", signature = "
+          + newMethod.getMethod().getClass() + ", signature = "
           + getApiSignature());
     }
     StringBuffer sb = new StringBuffer();
     if (firstType.getSimpleSourceName().indexOf("void") != -1) {
       return null;
     }
-    boolean compatible = ApiDiffGenerator.isFirstTypeAssignableToSecond(
-        secondType, firstType);
+    boolean compatible =
+        ApiDiffGenerator.isFirstTypeAssignableToSecond(secondType, firstType);
     if (compatible) {
       return null;
     }
@@ -57,33 +57,32 @@
     sb.append(firstType.getQualifiedSourceName());
     sb.append(" to ");
     sb.append(secondType.getQualifiedSourceName());
-    return new ApiChange(ApiChange.Status.RETURN_TYPE_ERROR, sb.toString());
+    return new ApiChange(this, ApiChange.Status.RETURN_TYPE_ERROR,
+        sb.toString());
   }
 
   /*
-   * check for: (i) added 'final' or 'abstract', (ii) removed 'static' adding
+   * check for: (i) added 'final' or 'abstract', (ii) removed 'static', adding
    * the 'static' keyword is fine.
    * 
    * A private, static, or final method can't be made 'abstract' (Java language
    * specification).
    */
   @Override
-  public ArrayList<ApiChange.Status> getModifierChanges(
-      final ApiAbstractMethod newMethod) {
+  List<ApiChange.Status> getModifierChanges(final ApiAbstractMethod newMethod) {
     JMethod newjmethod = null;
     JMethod oldjmethod = null;
 
-    if (newMethod.getMethodObject() instanceof JMethod
-        && method instanceof JMethod) {
-      newjmethod = (JMethod) newMethod.getMethodObject();
+    if (newMethod.getMethod() instanceof JMethod && method instanceof JMethod) {
+      newjmethod = (JMethod) newMethod.getMethod();
       oldjmethod = (JMethod) method;
     } else {
       throw new AssertionError("Different types for method = "
           + method.getClass() + " and newMethod = "
-          + newMethod.getMethodObject().getClass() + ", signature = "
+          + newMethod.getMethod().getClass() + ", signature = "
           + getApiSignature());
     }
-    ArrayList<ApiChange.Status> statuses = new ArrayList<ApiChange.Status>();
+    List<ApiChange.Status> statuses = new ArrayList<ApiChange.Status>();
     if (!oldjmethod.isFinal() && newjmethod.isFinal()) {
       statuses.add(ApiChange.Status.FINAL_ADDED);
     }
diff --git a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiPackage.java b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiPackage.java
index ca8a224..f1af3ac 100644
--- a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiPackage.java
+++ b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiPackage.java
@@ -22,53 +22,48 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
-import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
 
 /**
- * Encapsulates an API package.
+ * An immutable class that encapsulates an API package.
  */
-public class ApiPackage {
-  /**
-   * A package is an API package if it contains at least one API class. Refer
-   * http://wiki.eclipse.org/index.php/Evolving_Java-based_APIs This definition
-   * boils down to "a package is an API package iff it contains at least one API
-   * class that is not enclosed in any other class."
-   * 
-   * @return return true if and only if the packageObject is an apiPackage
-   */
-  public static boolean isApiPackage(JPackage packageObject) {
-    JClassType classTypes[] = packageObject.getTypes();
-    for (JClassType classType : classTypes) {
-      if (ApiClass.isPublicOuterClass(classType)) {
-        return true;
-      }
-    }
-    return false;
-  }
+final class ApiPackage implements Comparable<ApiPackage>, ApiElement {
 
-  private HashMap<String, ApiClass> apiClasses = new HashMap<String, ApiClass>();
-  private ApiContainer container = null;
+  private Map<String, ApiClass> apiClasses = new HashMap<String, ApiClass>();
+  private final ApiContainer apiContainer;
+  private final TreeLogger logger;
+  private final String name;
+  private final JPackage packageObject;
 
-  private TreeLogger logger = null;
-  private String name = null;
-
-  private JPackage packageObject = null;
-
-  public ApiPackage(JPackage obj, ApiContainer container) {
+  ApiPackage(JPackage obj, ApiContainer container) {
     packageObject = obj;
-    this.container = container;
-    if (logger == null) {
-      logger = container.getLogger();
-    }
+    this.apiContainer = container;
+    logger = container.getLogger();
     name = obj.getName();
     initialize();
   }
 
-  public ArrayList<JClassType> getAllClasses() {
-    ArrayList<JClassType> allClasses = new ArrayList<JClassType>(
-        Arrays.asList(packageObject.getTypes()));
+  public int compareTo(ApiPackage other) {
+    return this.getName().compareTo(other.getName());
+  }
+
+  public String getRelativeSignature() {
+    return name;
+  }
+
+  @Override
+  public String toString() {
+    return name;
+  }
+
+  List<JClassType> getAllClasses() {
+    List<JClassType> allClasses =
+        new ArrayList<JClassType>(Arrays.asList(packageObject.getTypes()));
     logger.log(TreeLogger.SPAM, "API " + packageObject + " has "
         + allClasses.size() + " outer classes", null);
     int index = 0;
@@ -82,33 +77,46 @@
     return allClasses;
   }
 
-  public ApiClass getApiClass(String className) {
+  String getApiAsString() {
+    StringBuffer sb = new StringBuffer();
+    sb.append(name + "\n");
+    ArrayList<ApiClass> apiClassesList =
+        new ArrayList<ApiClass>(apiClasses.values());
+    Collections.sort(apiClassesList);
+    for (ApiClass apiClass : apiClassesList) {
+      sb.append(apiClass.getApiAsString());
+    }
+    return sb.toString();
+  }
+
+  ApiClass getApiClass(String className) {
     return apiClasses.get(className);
   }
 
-  public HashSet<String> getApiClassNames() {
+  Set<ApiClass> getApiClassesBySet(Set<String> classNames) {
+    Set<ApiClass> set = new HashSet<ApiClass>();
+    for (String className : classNames) {
+      set.add(getApiClass(className));
+    }
+    return set;
+  }
+
+  Set<String> getApiClassNames() {
     return new HashSet<String>(apiClasses.keySet());
   }
 
-  public ApiContainer getApiContainer() {
-    return container;
+  ApiContainer getApiContainer() {
+    return apiContainer;
   }
 
-  public String getName() {
-    return name;
-  }
-
-  @Override
-  public String toString() {
+  String getName() {
     return name;
   }
 
   private void initialize() {
-    Iterator<JClassType> allClassesIterator = getAllClasses().iterator();
     ArrayList<String> notAddedClassNames = new ArrayList<String>();
-    while (allClassesIterator.hasNext()) {
-      JClassType classType = allClassesIterator.next();
-      if (ApiClass.isApiClass(classType)) {
+    for (JClassType classType : getAllClasses()) {
+      if (apiContainer.isApiClass(classType)) {
         ApiClass apiClass = new ApiClass(classType, this);
         apiClasses.put(classType.getQualifiedSourceName(), apiClass);
       } else {
diff --git a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiPackageDiffGenerator.java b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiPackageDiffGenerator.java
index 964bcab..c2353cf 100644
--- a/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiPackageDiffGenerator.java
+++ b/tools/api-checker/src/com/google/gwt/tools/apichecker/ApiPackageDiffGenerator.java
@@ -18,93 +18,100 @@
 
 import com.google.gwt.core.ext.typeinfo.NotFoundException;
 
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
 import java.util.HashMap;
-import java.util.HashSet;
-import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
 
 /**
  * encapsulates a class that produces the diff between the api of two packages.
  */
-public class ApiPackageDiffGenerator {
-  ApiDiffGenerator apiDiffGenerator = null;
-  HashMap<String, ApiClassDiffGenerator> intersectingClasses = new HashMap<String, ApiClassDiffGenerator>();
-  HashSet<String> missingClassNames = null;
-  String name = null;
-  ApiPackage newPackage = null;
-  ApiPackage oldPackage = null;
+final class ApiPackageDiffGenerator implements
+    Comparable<ApiPackageDiffGenerator> {
+  private final ApiDiffGenerator apiDiffGenerator;
+  private Map<String, ApiClassDiffGenerator> intersectingClasses =
+      new HashMap<String, ApiClassDiffGenerator>();
+  private Set<String> missingClassNames = null;
+  private final String name;
+  private final ApiPackage newPackage;
+  private final ApiPackage oldPackage;
 
-  public ApiPackageDiffGenerator(String packageName,
-      ApiDiffGenerator apiDiffGenerator) throws NotFoundException {
+  ApiPackageDiffGenerator(String packageName, ApiDiffGenerator apiDiffGenerator)
+      throws NotFoundException {
     this.apiDiffGenerator = apiDiffGenerator;
     name = packageName;
-    newPackage = apiDiffGenerator.getNewApiContainer().getApiPackage(
-        packageName);
-    oldPackage = apiDiffGenerator.getOldApiContainer().getApiPackage(
-        packageName);
+    newPackage =
+        apiDiffGenerator.getNewApiContainer().getApiPackage(packageName);
+    oldPackage =
+        apiDiffGenerator.getOldApiContainer().getApiPackage(packageName);
     if (newPackage == null || oldPackage == null) {
       throw new NotFoundException("for package " + packageName
           + ", one of the package objects is null");
     }
   }
 
-  public void cleanApiDiff() {
-    Iterator<ApiClassDiffGenerator> tempIterator = intersectingClasses.values().iterator();
-    while (tempIterator.hasNext()) {
-      tempIterator.next().cleanApiDiff();
+  public int compareTo(ApiPackageDiffGenerator other) {
+    return this.getName().compareTo(other.getName());
+  }
+
+  void cleanApiDiff() {
+    for (ApiClassDiffGenerator intersectingClass : intersectingClasses.values()) {
+      intersectingClass.cleanApiDiff();
     }
   }
 
-  public void computeApiDiff() throws NotFoundException {
-    HashSet<String> newClassNames = newPackage.getApiClassNames();
+  void computeApiDiff() throws NotFoundException {
+    Set<String> newClassNames = newPackage.getApiClassNames();
     missingClassNames = oldPackage.getApiClassNames();
-    HashSet<String> intersection = ApiDiffGenerator.extractCommonElements(
-        newClassNames, missingClassNames);
+    Set<String> intersection =
+        ApiDiffGenerator.removeIntersection(newClassNames, missingClassNames);
 
     /* Inspect each of the classes in each of the packages in the intersection */
-    Iterator<String> tempIterator = intersection.iterator();
-    while (tempIterator.hasNext()) {
-      String className = tempIterator.next();
-      ApiClassDiffGenerator temp = new ApiClassDiffGenerator(className, this);
-      intersectingClasses.put(className, temp);
-      temp.computeApiDiff();
+    for (String className : intersection) {
+      ApiClassDiffGenerator tempClassDiffGenerator =
+          new ApiClassDiffGenerator(className, this);
+      intersectingClasses.put(className, tempClassDiffGenerator);
+      tempClassDiffGenerator.computeApiDiff();
     }
   }
 
-  public ApiClassDiffGenerator findApiClassDiffGenerator(String key) {
+  ApiClassDiffGenerator findApiClassDiffGenerator(String key) {
     return intersectingClasses.get(key);
   }
 
-  public ApiDiffGenerator getApiDiffGenerator() {
+  Collection<ApiChange> getApiDiff() {
+    Collection<ApiChange> collection = new ArrayList<ApiChange>();
+    Collection<ApiClass> missingClasses =
+        oldPackage.getApiClassesBySet(missingClassNames);
+    for (ApiClass missingClass : missingClasses) {
+      collection.add(new ApiChange(missingClass, ApiChange.Status.MISSING));
+    }
+    List<ApiClassDiffGenerator> intersectingClassesList =
+        new ArrayList<ApiClassDiffGenerator>(intersectingClasses.values());
+    Collections.sort(intersectingClassesList);
+    for (ApiClassDiffGenerator intersectingClass : intersectingClasses.values()) {
+      collection.addAll(intersectingClass.getApiDiff());
+    }
+    return collection;
+  }
+
+  ApiDiffGenerator getApiDiffGenerator() {
     return apiDiffGenerator;
   }
 
-  public ApiPackage getNewApiPackage() {
+  String getName() {
+    return name;
+  }
+
+  ApiPackage getNewApiPackage() {
     return newPackage;
   }
 
-  public ApiPackage getOldApiPackage() {
+  ApiPackage getOldApiPackage() {
     return oldPackage;
   }
 
-  public String printApiDiff() {
-    int totalSize = missingClassNames.size() + intersectingClasses.size();
-    if (totalSize == 0) {
-      return "";
-    }
-    StringBuffer sb = new StringBuffer();
-    Iterator<String> missingClassesIterator = missingClassNames.iterator();
-    while (missingClassesIterator.hasNext()) {
-      sb.append("\t\t" + missingClassesIterator.next()
-          + ApiDiffGenerator.DELIMITER + ApiChange.Status.MISSING + "\n");
-    }
-    Iterator<ApiClassDiffGenerator> tempIterator = intersectingClasses.values().iterator();
-    while (tempIterator.hasNext()) {
-      sb.append(tempIterator.next().printApiDiff());
-    }
-    if (sb.length() == 0) {
-      return "";
-    }
-    return "\tpackage " + name + "\n" + sb.toString() + "\n";
-  }
-
 }
diff --git a/tools/api-checker/test/com/google/gwt/tools/apichecker/ApiCompatibilityTest.java b/tools/api-checker/test/com/google/gwt/tools/apichecker/ApiCompatibilityTest.java
index b643388..514bfa6 100644
--- a/tools/api-checker/test/com/google/gwt/tools/apichecker/ApiCompatibilityTest.java
+++ b/tools/api-checker/test/com/google/gwt/tools/apichecker/ApiCompatibilityTest.java
@@ -18,17 +18,14 @@
 import com.google.gwt.core.ext.TreeLogger;
 import com.google.gwt.core.ext.UnableToCompleteException;
 import com.google.gwt.core.ext.typeinfo.NotFoundException;
-import com.google.gwt.core.ext.typeinfo.TypeOracle;
-import com.google.gwt.dev.javac.CompilationUnit;
-import com.google.gwt.dev.javac.JdtCompiler;
-import com.google.gwt.dev.javac.TypeOracleMediator;
 import com.google.gwt.dev.util.log.AbstractTreeLogger;
 import com.google.gwt.dev.util.log.PrintWriterTreeLogger;
+import com.google.gwt.tools.apichecker.ApiContainerTest.StaticCompilationUnit;
 
 import junit.framework.TestCase;
 
+import java.util.Collection;
 import java.util.HashSet;
-import java.util.Set;
 
 /**
  * 
@@ -42,48 +39,20 @@
  */
 public class ApiCompatibilityTest extends TestCase {
 
-  static class StaticCompilationUnit extends CompilationUnit {
-
-    private final char[] source;
-    private final String typeName;
-
-    public StaticCompilationUnit(String typeName, char[] source) {
-      this.typeName = typeName;
-      this.source = source;
-    }
-
-    @Override
-    public String getDisplayLocation() {
-      return "/mock/" + typeName;
-    }
-
-    @Override
-    public String getSource() {
-      return String.valueOf(source);
-    }
-
-    @Override
-    public String getTypeName() {
-      return typeName;
-    }
-
-    @Override
-    public boolean isGenerated() {
-      return false;
-    }
-  }
-
   // These cups are slightly different from the cups in ApiContainerTest
-  static StaticCompilationUnit cuApiClass = new StaticCompilationUnit(
-      "test.apicontainer.ApiClass", getSourceForApiClass());
-  static StaticCompilationUnit cuNonApiClass = new StaticCompilationUnit(
-      "test.apicontainer.NonApiClass", getSourceForNonApiClass());
-  static StaticCompilationUnit cuNonApiPackage = new StaticCompilationUnit(
-      "test.nonapipackage.TestClass", getSourceForTestClass());
-  static StaticCompilationUnit cuObject = new StaticCompilationUnit(
-      "java.lang.Object", getSourceForObject());
-  static StaticCompilationUnit cuThrowable = new StaticCompilationUnit(
-      "java.lang.Throwable", getSourceForThrowable());
+
+  private static StaticCompilationUnit[] getScuArray() {
+    return new StaticCompilationUnit[] {
+        new StaticCompilationUnit("test.apicontainer.ApiClass",
+            getSourceForApiClass()),
+        new StaticCompilationUnit("test.apicontainer.NonApiClass",
+            getSourceForNonApiClass()),
+        new StaticCompilationUnit("test.nonapipackage.TestClass",
+            getSourceForTestClass()),
+        new StaticCompilationUnit("java.lang.Object", getSourceForObject()),
+        new StaticCompilationUnit("java.lang.Throwable",
+            getSourceForThrowable()),};
+  }
 
   private static char[] getSourceForApiClass() {
     StringBuffer sb = new StringBuffer();
@@ -142,49 +111,46 @@
 
   ApiContainer api1 = null;
   ApiContainer api2 = null;
-
   ApiContainer apiSameAs1 = null;
 
-  public TypeOracle getNewTypeOracleWithCompilationUnitsAdded(
-      AbstractTreeLogger logger) throws UnableToCompleteException {
-    TypeOracleMediator mediator = new TypeOracleMediator();
-    Set<CompilationUnit> units = new HashSet<CompilationUnit>();
-    units.add(cuObject);
-    units.add(cuNonApiClass);
-    units.add(cuApiClass);
-    units.add(cuNonApiPackage);
-    units.add(cuThrowable);
-    JdtCompiler.compile(units);
-    mediator.refresh(logger, units);
-    return mediator.getTypeOracle();
-  }
-
   @Override
-  public void setUp() {
+  public void setUp() throws UnableToCompleteException {
     AbstractTreeLogger logger = new PrintWriterTreeLogger();
     logger.setMaxDetail(TreeLogger.ERROR);
-    try {
-      api1 = new ApiContainer("Api1", logger,
-          new ApiContainerTest().getNewTypeOracleWithCompilationUnitsAdded());
-      apiSameAs1 = new ApiContainer("Api2", logger,
-          new ApiContainerTest().getNewTypeOracleWithCompilationUnitsAdded());
-      api2 = new ApiContainer("Api2", logger,
-          getNewTypeOracleWithCompilationUnitsAdded(logger));
-    } catch (Exception ex) {
-      assertEquals("JSNI checks are probably active", "failed");
-    }
+
+    api1 =
+        new ApiContainer("Api1", logger,
+            ApiContainerTest.getNewTypeOracleFromCompilationUnits(
+                ApiContainerTest.getScuArray(), logger));
+    apiSameAs1 =
+        new ApiContainer("Api2", logger,
+            ApiContainerTest.getNewTypeOracleFromCompilationUnits(
+                ApiContainerTest.getScuArray(), logger));
+    api2 =
+        new ApiContainer("Api2", logger,
+            ApiContainerTest.getNewTypeOracleFromCompilationUnits(
+                getScuArray(), logger));
   }
 
-  public void testBasicStuff() throws NotFoundException {
+  // setup is called before every test*. To avoid the overhead of setUp() each
+  // time, test everything together.
+  public void testEverything() throws NotFoundException {
+    checkBasicStuff();
+    checkWhiteList();
+  }
+
+  private void checkBasicStuff() throws NotFoundException {
     HashSet<String> hashSet = new HashSet<String>();
-    assertEquals("", ApiCompatibilityChecker.getApiDiff(new ApiDiffGenerator(
-        api1, apiSameAs1), hashSet, false));
+    assertEquals(0, ApiCompatibilityChecker.getApiDiff(api1, apiSameAs1,
+        hashSet).size());
     ApiDiffGenerator apiDiff = new ApiDiffGenerator(api2, api1);
     boolean removeDuplicates = false;
-    String strWithDuplicates = ApiCompatibilityChecker.getApiDiff(apiDiff,
-        hashSet, removeDuplicates);
-    String strWithoutDuplicates = ApiCompatibilityChecker.getApiDiff(apiDiff,
-        hashSet, !removeDuplicates);
+    String strWithDuplicates =
+        getStringRepresentation(ApiCompatibilityChecker.getApiDiff(apiDiff,
+            hashSet, removeDuplicates));
+    String strWithoutDuplicates =
+        getStringRepresentation(ApiCompatibilityChecker.getApiDiff(apiDiff,
+            hashSet, !removeDuplicates));
 
     String delimiter = ApiDiffGenerator.DELIMITER;
     // test if missing packages are reported correctly
@@ -204,15 +170,14 @@
         "test.apicontainer.NonApiClass.ApiClassInNonApiClass" + delimiter
             + ApiChange.Status.ABSTRACT_ADDED, strWithoutDuplicates));
 
-    // test if methods are reported as missing due to class becoming abstract
-    if (ApiCompatibilityChecker.REMOVE_ABSTRACT_CLASS_FROM_API) {
-      assertEquals(1, countPresence(
-          "test.apicontainer.NonApiClass.ApiClassInNonApiClass::ApiClassInNonApiClass()"
-              + delimiter + ApiChange.Status.MISSING, strWithoutDuplicates));
-      assertEquals(1, countPresence(
-          "test.apicontainer.NonApiClass.ApiClassInNonApiClass::protectedMethod()"
-              + delimiter + ApiChange.Status.MISSING, strWithoutDuplicates));
-    }
+    // test if methods are staill reported even if class becomes abstract (as
+    // long as it is sub-classable)
+    assertEquals(0, countPresence(
+        "test.apicontainer.NonApiClass.ApiClassInNonApiClass::ApiClassInNonApiClass()"
+            + delimiter + ApiChange.Status.MISSING, strWithoutDuplicates));
+    assertEquals(0, countPresence(
+        "test.apicontainer.NonApiClass.ApiClassInNonApiClass::protectedMethod()"
+            + delimiter + ApiChange.Status.MISSING, strWithoutDuplicates));
 
     // test if modifier changes of fields and methods are reported
     assertEquals(1, countPresence("java.lang.Object::apiField" + delimiter
@@ -220,21 +185,26 @@
     assertEquals(1, countPresence("java.lang.Object::protectedMethod()"
         + delimiter + ApiChange.Status.FINAL_ADDED, strWithoutDuplicates));
 
-    // test if duplicates are weeded out.
-    if (ApiCompatibilityChecker.REMOVE_ABSTRACT_CLASS_FROM_API) {
-      assertEquals(2, countPresence("protectedMethod()" + delimiter
-          + ApiChange.Status.FINAL_ADDED, strWithDuplicates));
-    } else {
-      assertEquals(3, countPresence("protectedMethod()" + delimiter
-          + ApiChange.Status.FINAL_ADDED, strWithDuplicates));
-    }
+    // test if duplicates are weeded out from intersecting methods
+    assertEquals(3, countPresence("protectedMethod()" + delimiter
+        + ApiChange.Status.FINAL_ADDED, strWithDuplicates));
+    assertEquals(1, countPresence("protectedMethod()" + delimiter
+        + ApiChange.Status.FINAL_ADDED, strWithoutDuplicates));
+
+    // test if duplicates are weeded out from missing fields
+    assertEquals(3, countPresence("apiFieldWillBeMissing" + delimiter
+        + ApiChange.Status.MISSING, strWithDuplicates));
+    assertEquals(1, countPresence("apiFieldWillBeMissing" + delimiter
+        + ApiChange.Status.MISSING, strWithoutDuplicates));
+
     // test returnType error
-    String methodSignature = "checkParametersAndReturnTypes(Ltest/apicontainer/ApiClass;)";
+    String methodSignature =
+        "checkParametersAndReturnTypes(Ltest/apicontainer/ApiClass;)";
     assertEquals(1, countPresence(methodSignature + delimiter
         + ApiChange.Status.RETURN_TYPE_ERROR, strWithoutDuplicates));
     // test method exceptions
     assertEquals(1, countPresence(methodSignature + delimiter
-        + ApiChange.Status.EXCEPTIONS_ERROR, strWithoutDuplicates));
+        + ApiChange.Status.EXCEPTION_TYPE_ERROR, strWithoutDuplicates));
 
     // checking if changes in parameter types were okay
     assertEquals(2, countPresence(methodSignature, strWithoutDuplicates));
@@ -242,18 +212,20 @@
     // test method_overloading
     methodSignature = "methodInNonApiClass(Ljava/lang/Object;)";
     assertEquals(1, countPresence(methodSignature + delimiter
-        + ApiChange.Status.OVERLOADED, strWithoutDuplicates));
+        + ApiChange.Status.OVERLOADED_METHOD_CALL, strWithoutDuplicates));
   }
 
-  public void testWhiteList() throws NotFoundException {
+  private void checkWhiteList() throws NotFoundException {
     ApiDiffGenerator apiDiff = new ApiDiffGenerator(api2, api1);
     boolean removeDuplicates = false;
-    String whiteList = "java.newpackage" + ApiDiffGenerator.DELIMITER
-        + ApiChange.Status.MISSING;
+    String whiteList =
+        "java.newpackage" + ApiDiffGenerator.DELIMITER
+            + ApiChange.Status.MISSING;
     HashSet<String> hashSet = new HashSet<String>();
     hashSet.add(whiteList);
-    String strWithoutDuplicates = ApiCompatibilityChecker.getApiDiff(apiDiff,
-        hashSet, !removeDuplicates);
+    String strWithoutDuplicates =
+        getStringRepresentation(ApiCompatibilityChecker.getApiDiff(apiDiff,
+            hashSet, !removeDuplicates));
 
     // test if missing packages are reported correctly
     assertEquals(0, countPresence(whiteList, strWithoutDuplicates));
@@ -269,10 +241,20 @@
     return count;
   }
 
+  private String getStringRepresentation(Collection<ApiChange> collection) {
+    StringBuffer sb = new StringBuffer();
+    for (ApiChange apiChange : collection) {
+      sb.append(apiChange.getApiElement().getRelativeSignature());
+      sb.append(ApiDiffGenerator.DELIMITER);
+      sb.append(apiChange.getStatus());
+      sb.append("\n");
+    }
+    return sb.toString();
+  }
+
 }
 
 // abstract methods can't be static
-
 class TestAA {
   static int j = 10;
 
diff --git a/tools/api-checker/test/com/google/gwt/tools/apichecker/ApiContainerTest.java b/tools/api-checker/test/com/google/gwt/tools/apichecker/ApiContainerTest.java
index a390b08..c2d17fa 100644
--- a/tools/api-checker/test/com/google/gwt/tools/apichecker/ApiContainerTest.java
+++ b/tools/api-checker/test/com/google/gwt/tools/apichecker/ApiContainerTest.java
@@ -15,7 +15,6 @@
  */
 package com.google.gwt.tools.apichecker;
 
-import com.google.gwt.core.ext.TreeLogger;
 import com.google.gwt.core.ext.UnableToCompleteException;
 import com.google.gwt.core.ext.typeinfo.JAbstractMethod;
 import com.google.gwt.core.ext.typeinfo.TypeOracle;
@@ -24,10 +23,10 @@
 import com.google.gwt.dev.javac.TypeOracleMediator;
 import com.google.gwt.dev.util.log.AbstractTreeLogger;
 import com.google.gwt.dev.util.log.PrintWriterTreeLogger;
-import com.google.gwt.tools.apichecker.ApiCompatibilityTest.StaticCompilationUnit;
 
 import junit.framework.TestCase;
 
+import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Set;
 
@@ -35,6 +34,37 @@
  * Test ApiContainer.
  */
 public class ApiContainerTest extends TestCase {
+  static class StaticCompilationUnit extends CompilationUnit {
+
+    private final char[] source;
+    private final String typeName;
+
+    public StaticCompilationUnit(String typeName, char[] source) {
+      this.typeName = typeName;
+      this.source = source;
+    }
+
+    @Override
+    public String getDisplayLocation() {
+      return "/mock/" + typeName;
+    }
+
+    @Override
+    public String getSource() {
+      return String.valueOf(source);
+    }
+
+    @Override
+    public String getTypeName() {
+      return typeName;
+    }
+
+    @Override
+    public boolean isGenerated() {
+      return false;
+    }
+  }
+
   @SuppressWarnings("unused")
   class TestA {
     public TestA(String args) {
@@ -51,7 +81,6 @@
       return "";
     }
   }
-
   class TestB extends TestA {
     public TestB(TestA a) {
       super(a);
@@ -65,20 +94,34 @@
     }
   }
 
-  static StaticCompilationUnit cuApiClass = new StaticCompilationUnit(
-      "test.apicontainer.ApiClass", getSourceForApiClass());
-  static StaticCompilationUnit cuNonApiClass = new StaticCompilationUnit(
-      "test.apicontainer.NonApiClass", getSourceForNonApiClass());
-  static StaticCompilationUnit cuNonApiPackage = new StaticCompilationUnit(
-      "test.nonapipackage.TestClass", getSourceForTestClass());
-  static StaticCompilationUnit cuObject = new StaticCompilationUnit(
-      "java.lang.Object", getSourceForObject());
-  static StaticCompilationUnit cuNewPackage = new StaticCompilationUnit(
-      "java.newpackage.Test", getSourceForTest());
+  // TODO (amitmanjhi): Try using UnitTestTreeLogger to capture log messages
+  public static TypeOracle getNewTypeOracleFromCompilationUnits(
+      StaticCompilationUnit tempScuArray[], AbstractTreeLogger logger)
+      throws UnableToCompleteException {
+
+    TypeOracleMediator mediator = new TypeOracleMediator();
+    Set<CompilationUnit> units =
+        new HashSet<CompilationUnit>(Arrays.asList(tempScuArray));
+    JdtCompiler.compile(units);
+    mediator.refresh(logger, units);
+    return mediator.getTypeOracle();
+  }
+
+  public static StaticCompilationUnit[] getScuArray() {
+    return new StaticCompilationUnit[] {
+        new StaticCompilationUnit("test.apicontainer.ApiClass",
+            getSourceForApiClass()),
+        new StaticCompilationUnit("test.apicontainer.NonApiClass",
+            getSourceForNonApiClass()),
+        new StaticCompilationUnit("test.nonapipackage.TestClass",
+            getSourceForTestClass()),
+        new StaticCompilationUnit("java.lang.Object", getSourceForObject()),
+        new StaticCompilationUnit("java.newpackage.Test", getSourceForTest()),};
+  }
 
   private static JAbstractMethod getMethodByName(String name, ApiClass apiClass) {
     return (apiClass.getApiMethodsByName(name, ApiClass.MethodType.METHOD).toArray(
-        new ApiAbstractMethod[0])[0]).getMethodObject();
+        new ApiAbstractMethod[0])[0]).getMethod();
   }
 
   private static char[] getSourceForApiClass() {
@@ -91,6 +134,18 @@
     return sb.toString().toCharArray();
   }
 
+  private static char[] getSourceForNewObject() {
+    StringBuffer sb = new StringBuffer();
+    sb.append("package java.lang;\n");
+    sb.append("public class Object {\n");
+    sb.append("\tpublic static class Foo extends Object{\n");
+    sb.append("\t}\n");
+    sb.append("}\n");
+    sb.append("class Temp {\n");
+    sb.append("}");
+    return sb.toString().toCharArray();
+  }
+
   private static char[] getSourceForNonApiClass() {
     StringBuffer sb = new StringBuffer();
     sb.append("package test.apicontainer;\n");
@@ -115,6 +170,7 @@
     sb.append("\tprivate void internalMethod() { }\n");
     sb.append("\tprotected native long protectedMethod();\n");
     sb.append("\tpublic int apiField = 0;\n");
+    sb.append("\tprotected transient int apiFieldWillBeMissing = 1;\n");
     sb.append("\tprivate int internalField = 0;\n");
     sb.append("\tprotected int protectedField=2;\n");
     sb.append("}\n");
@@ -137,27 +193,8 @@
     return sb.toString().toCharArray();
   }
 
-  ApiContainer api1 = null;
-
-  // TODO (amitmanjhi): Try using UnitTestTreeLogger to capture log messages
-  public TypeOracle getNewTypeOracleWithCompilationUnitsAdded()
-      throws UnableToCompleteException {
-
-    AbstractTreeLogger logger = new PrintWriterTreeLogger();
-    logger.setMaxDetail(TreeLogger.ERROR);
-
-    // Build onto an empty type oracle.
-    TypeOracleMediator mediator = new TypeOracleMediator();
-    Set<CompilationUnit> units = new HashSet<CompilationUnit>();
-    units.add(cuObject);
-    units.add(cuNonApiClass);
-    units.add(cuApiClass);
-    units.add(cuNonApiPackage);
-    units.add(cuNewPackage);
-    JdtCompiler.compile(units);
-    mediator.refresh(logger, units);
-    return mediator.getTypeOracle();
-  }
+  ApiContainer apiCheck = null;
+  ApiContainer apiCheckLoop = null;
 
   /**
    * Class hierarchy. public java.lang.Object -- test.apicontainer.NonApiClass
@@ -165,26 +202,34 @@
    * test.apicontainer.ApiClass -- test.nonapipackage.TestClass
    */
   @Override
-  public void setUp() {
-    AbstractTreeLogger logger1 = new PrintWriterTreeLogger();
-    logger1.setMaxDetail(TreeLogger.ERROR);
+  public void setUp() throws UnableToCompleteException {
+    AbstractTreeLogger logger = new PrintWriterTreeLogger();
+    logger.setMaxDetail(com.google.gwt.core.ext.TreeLogger.ERROR);
+    apiCheckLoop =
+        new ApiContainer("ApiClassTest", logger,
+            getNewTypeOracleFromCompilationUnits(
+                new StaticCompilationUnit[] {new StaticCompilationUnit(
+                    "java.lang.Object", getSourceForNewObject()),}, logger));
 
-    try {
-      api1 = new ApiContainer("ApiContainerTest", logger1,
-          getNewTypeOracleWithCompilationUnitsAdded());
-    } catch (Exception ex) {
-      // JSNI checks are active.
-      assertEquals("jsni checks are probably active", "failed");
-    }
+    apiCheck =
+        new ApiContainer("ApiContainerTest", logger,
+            getNewTypeOracleFromCompilationUnits(getScuArray(), logger));
+  }
+
+  public void testEverything() {
+    checkApiClass();
+    checkApiMembers();
+    checkApiPackages();
+    checkInfiniteLoopInApiClass();
   }
 
   /**
    * Check if apiClasses are determined correctly. Check if inner classes are
    * classified correctly as api classes.
    */
-  public void testApiClass() {
-    ApiPackage package1 = api1.getApiPackage("java.lang");
-    ApiPackage package2 = api1.getApiPackage("test.apicontainer");
+  void checkApiClass() {
+    ApiPackage package1 = apiCheck.getApiPackage("java.lang");
+    ApiPackage package2 = apiCheck.getApiPackage("test.apicontainer");
     assertNotNull(package1);
     assertNotNull(package2);
 
@@ -205,21 +250,23 @@
    * apiMethods, (b) method overloading is done correctly
    * 
    */
-  public void testApiMembers() {
-    ApiClass object = api1.getApiPackage("java.lang").getApiClass(
-        "java.lang.Object");
-    ApiClass apiClass = api1.getApiPackage("test.apicontainer").getApiClass(
-        "test.apicontainer.ApiClass");
-    ApiClass innerClass = api1.getApiPackage("test.apicontainer").getApiClass(
-        "test.apicontainer.NonApiClass.ApiClassInNonApiClass");
+  void checkApiMembers() {
+    ApiClass object =
+        apiCheck.getApiPackage("java.lang").getApiClass("java.lang.Object");
+    ApiClass apiClass =
+        apiCheck.getApiPackage("test.apicontainer").getApiClass(
+            "test.apicontainer.ApiClass");
+    ApiClass innerClass =
+        apiCheck.getApiPackage("test.apicontainer").getApiClass(
+            "test.apicontainer.NonApiClass.ApiClassInNonApiClass");
 
     // constructors
     assertEquals(1, innerClass.getApiMemberNames(
         ApiClass.MethodType.CONSTRUCTOR).size());
 
     // fields
-    assertEquals(2, object.getApiFieldNames().size());
-    assertEquals(3, apiClass.getApiFieldNames().size());
+    assertEquals(3, object.getApiFieldNames().size());
+    assertEquals(4, apiClass.getApiFieldNames().size());
 
     // methods
     assertEquals(2, object.getApiMemberNames(ApiClass.MethodType.METHOD).size());
@@ -236,10 +283,16 @@
   /**
    * Test if apiPackages are identified correctly.
    */
-  public void testApiPackages() {
-    assertNotNull(api1.getApiPackage("java.lang"));
-    assertNotNull(api1.getApiPackage("test.apicontainer"));
-    assertEquals(3, api1.getApiPackageNames().size());
+  void checkApiPackages() {
+    assertNotNull(apiCheck.getApiPackage("java.lang"));
+    assertNotNull(apiCheck.getApiPackage("test.apicontainer"));
+    assertEquals(3, apiCheck.getApiPackageNames().size());
   }
 
+  void checkInfiniteLoopInApiClass() {
+    ApiPackage tempPackage = apiCheckLoop.getApiPackage("java.lang");
+    assertNotNull(tempPackage);
+    assertNotNull(tempPackage.getApiClass("java.lang.Object"));
+    assertEquals(2, tempPackage.getApiClassNames().size());
+  }
 }