diff --git a/dev/build.xml b/dev/build.xml
index 69962fd..37ffb3e 100755
--- a/dev/build.xml
+++ b/dev/build.xml
@@ -79,44 +79,46 @@
           <include name="colt/colt-1.2.jar"/>
           <include name="eclipse/org.eclipse.jdt.core_3.17.0.v20190306-2240.jar"/>
           <include name="eclipse/jdtCompilerAdapter_3.17.0.v20190306-2240.jar"/>
-          <include name="objectweb/asm-7.1/asm-7.1.jar"/>
-          <include name="objectweb/asm-7.1/asm-commons-7.1.jar"/>
-          <include name="objectweb/asm-7.1/asm-util-7.1.jar"/>
+          <include name="objectweb/asm-9.2/asm-9.2.jar"/>
+          <include name="objectweb/asm-9.2/asm-commons-9.2.jar"/>
+          <include name="objectweb/asm-9.2/asm-util-9.2.jar"/>
           <include name="guava/guava-19.0/guava-19.0-rebased.jar"/>
           <include name="icu4j/63.1/icu4j.jar"/>
-          <include name="jetty/jetty-9.2.14.v20151106/jetty-all-9.2.14.v20151106.jar"/>
+          <include name="jetty/jetty-9.4.44.v20210927/jetty-all-9.4.44.v20210927.jar"/>
           <include name="gson/gson-2.6.2.jar"/>
           <include name="jscomp/20160315/sourcemap-rebased.jar"/>
           <include name="jsr305/jsr305.jar"/>
           <include name="protobuf/protobuf-2.5.0/protobuf-java-rebased-2.5.0.jar"/>
           <!-- dependencies needed for JSP support in DevMode: BEGIN -->
-          <include name="jetty/jetty-9.2.14.v20151106/mortbay-apache-jsp-8.0.9.M3.jar"/>
-          <include name="jetty/jetty-9.2.14.v20151106/mortbay-apache-el-8.0.9.M3.jar"/>
-          <include name="jetty/jetty-9.2.14.v20151106/jetty-apache-jsp-9.2.14.v20151106.jar"/>
+          <include name="jetty/jetty-9.4.44.v20210927/mortbay-apache-jsp-8.5.70.jar"/>
+          <include name="jetty/jetty-9.4.44.v20210927/mortbay-apache-el-8.5.70.jar"/>
+          <include name="jetty/jetty-9.4.44.v20210927/jetty-apache-jsp-9.4.44.v20210927.jar"/>
           <!-- dependencies needed for JSP support in DevMode: END -->
           <include name="tomcat/tomcat-servlet-api-8.0.28.jar"/>
           <include name="tomcat/tomcat-websocket-api-8.0.28.jar"/>
           <include name="tomcat/tomcat-annotations-api-8.0.28.jar"/>
           <include name="apache/commons/commons-collections-3.2.2.jar"/>
           <!-- htmlunit dependencies not already included: BEGIN -->
-          <include name="apache/http/httpclient-4.5.1.jar"/>
-          <include name="apache/http/httpcore-4.4.4.jar"/>
-          <include name="apache/http/httpmime-4.5.1.jar"/>
+          <include name="apache/http/httpclient-4.5.13.jar"/>
+          <include name="apache/http/httpcore-4.4.13.jar"/>
+          <include name="apache/http/httpmime-4.5.13.jar"/>
           <include name="apache/james/apache-mime4j-0.6.jar"/>
           <include name="apache/commons/commons-codec-1.10.jar"/>
           <include name="apache/commons/commons-io-2.4.jar"/>
           <include name="apache/commons/commons-lang3-3.4.jar"/>
           <include name="apache/commons/commons-logging-1.2.jar"/>
-          <include name="cssparser/cssparser-0.9.18.jar"/>
-         <include name="htmlunit/htmlunit-2.19/htmlunit-2.19.jar"/>
-         <include name="htmlunit/htmlunit-2.19/htmlunit-core-js-2.15.jar"/>
-          <include name="nekohtml/nekohtml-1.9.22.jar"/>
+          <include name="htmlunit/htmlunit-2.55.0/htmlunit-cssparser-1.10.0.jar"/>
+          <include name="htmlunit/htmlunit-2.55.0/htmlunit-2.55.0.jar"/>
+          <include name="htmlunit/htmlunit-2.55.0/htmlunit-core-js-2.55.0.jar"/>
+          <include name="htmlunit/htmlunit-2.55.0/neko-htmlunit-2.55.0.jar"/>
+          <include name="htmlunit/htmlunit-2.55.0/salvation2-3.0.0.jar"/>
           <include name="cup/java-cup-11a.jar"/>
           <include name="xalan/xalan-2.7.1-nocup.jar"/>
           <include name="xerces/xerces-2_11_0/serializer-2.7.1.jar"/>
           <include name="xerces/xerces-2_11_0/xercesImpl-2.11.0.jar"/>
           <include name="xerces/xerces-2_11_0/xml-apis-1.4.01.jar"/>
           <include name="w3c/sac/sac-1.3.jar"/>
+          <include name="brotli/dec-0.1.2.jar"/>
           <!-- htmlunit dependencies not already included: END -->
           <include name="json/android-sdk-19.1/json-android-rebased.jar"/>
         </fileset>
@@ -131,9 +133,9 @@
             <provider classname="org.eclipse.jetty.websocket.jsr356.server.deploy.WebSocketServerContainerInitializer"/>
             <provider classname="org.eclipse.jetty.apache.jsp.JettyJasperInitializer"/>
           </service>
-          <zipfileset src="${gwt.tools.lib}/objectweb/asm-7.1/asm-7.1.jar"/>
-          <zipfileset src="${gwt.tools.lib}/objectweb/asm-7.1/asm-commons-7.1.jar"/>
-          <zipfileset src="${gwt.tools.lib}/objectweb/asm-7.1/asm-util-7.1.jar"/>
+          <zipfileset src="${gwt.tools.lib}/objectweb/asm-9.2/asm-9.2.jar"/>
+          <zipfileset src="${gwt.tools.lib}/objectweb/asm-9.2/asm-commons-9.2.jar"/>
+          <zipfileset src="${gwt.tools.lib}/objectweb/asm-9.2/asm-util-9.2.jar"/>
           <zipfileset src="${gwt.tools.lib}/apache/tapestry-util-text-4.0.2.jar"/>
           <zipfileset src="${gwt.tools.lib}/apache/ant-zipscanner/ant-zipscanner-1.6.5-1-rebased.jar"/>
           <zipfileset src="${gwt.tools.lib}/colt/colt-1.2.jar"/>
@@ -144,16 +146,22 @@
           <zipfileset src="${gwt.tools.lib}/guava/guava-19.0/guava-19.0-rebased.jar"/>
           <zipfileset src="${gwt.tools.lib}/icu4j/63.1/icu4j.jar"/>
           <zipfileset
-              src="${gwt.tools.lib}/jetty/jetty-9.2.14.v20151106/jetty-all-9.2.14.v20151106.jar"/>
+              src="${gwt.tools.lib}/jetty/jetty-9.4.44.v20210927/jetty-all-9.4.44.v20210927.jar">
+            <!--
+            Don't add jetty auth implementation from jetty-jaspi, as we would also need to package jetty's
+            javax.security.auth.message implementation as well as geronimo-jaspi.
+             -->
+            <exclude name="META-INF/services/org.eclipse.jetty.security.Authenticator$Factory"/>
+          </zipfileset>
           <zipfileset src="${gwt.tools.lib}/gson/gson-2.6.2.jar"/>
           <zipfileset src="${gwt.tools.lib}/jscomp/20160315/sourcemap-rebased.jar"/>
           <zipfileset src="${gwt.tools.lib}/jsr305/jsr305.jar"/>
           <zipfileset
               src="${gwt.tools.lib}/protobuf/protobuf-2.5.0/protobuf-java-rebased-2.5.0.jar"/>
           <!-- dependencies needed for JSP support in DevMode: BEGIN -->
-          <zipfileset src="${gwt.tools.lib}/jetty/jetty-9.2.14.v20151106/mortbay-apache-jsp-8.0.9.M3.jar"/>
-          <zipfileset src="${gwt.tools.lib}/jetty/jetty-9.2.14.v20151106/mortbay-apache-el-8.0.9.M3.jar"/>
-          <zipfileset src="${gwt.tools.lib}/jetty/jetty-9.2.14.v20151106/jetty-apache-jsp-9.2.14.v20151106.jar"/>
+          <zipfileset src="${gwt.tools.lib}/jetty/jetty-9.4.44.v20210927/mortbay-apache-jsp-8.5.70.jar"/>
+          <zipfileset src="${gwt.tools.lib}/jetty/jetty-9.4.44.v20210927/mortbay-apache-el-8.5.70.jar"/>
+          <zipfileset src="${gwt.tools.lib}/jetty/jetty-9.4.44.v20210927/jetty-apache-jsp-9.4.44.v20210927.jar"/>
           <!-- dependencies needed for JSP support in DevMode: END -->
           <zipfileset src="${gwt.tools.lib}/tomcat/tomcat-servlet-api-8.0.28.jar"/>
           <zipfileset src="${gwt.tools.lib}/tomcat/tomcat-websocket-api-8.0.28.jar"/>
@@ -161,25 +169,27 @@
           <zipfileset
               src="${gwt.tools.lib}/apache/commons/commons-collections-3.2.2.jar"/>
           <!-- htmlunit dependencies not already included: BEGIN -->
-          <zipfileset src="${gwt.tools.lib}/apache/http/httpclient-4.5.1.jar"/>
-          <zipfileset src="${gwt.tools.lib}/apache/http/httpcore-4.4.4.jar"/>
-          <zipfileset src="${gwt.tools.lib}/apache/http/httpmime-4.5.1.jar"/>
+          <zipfileset src="${gwt.tools.lib}/apache/http/httpclient-4.5.13.jar"/>
+          <zipfileset src="${gwt.tools.lib}/apache/http/httpcore-4.4.13.jar"/>
+          <zipfileset src="${gwt.tools.lib}/apache/http/httpmime-4.5.13.jar"/>
           <zipfileset src="${gwt.tools.lib}/apache/james/apache-mime4j-0.6.jar"/>
           <zipfileset src="${gwt.tools.lib}/apache/commons/commons-codec-1.10.jar"/>
           <zipfileset src="${gwt.tools.lib}/apache/commons/commons-io-2.4.jar"/>
           <zipfileset src="${gwt.tools.lib}/apache/commons/commons-lang3-3.4.jar"/>
           <zipfileset src="${gwt.tools.lib}/apache/commons/commons-logging-1.2.jar"/>
-          <zipfileset src="${gwt.tools.lib}/cssparser/cssparser-0.9.18.jar"/>
-          <zipfileset src="${gwt.tools.lib}/htmlunit/htmlunit-2.19/htmlunit-2.19.jar"/>
+          <zipfileset src="${gwt.tools.lib}/htmlunit/htmlunit-2.55.0/htmlunit-cssparser-1.10.0.jar"/>
+          <zipfileset src="${gwt.tools.lib}/htmlunit/htmlunit-2.55.0/htmlunit-2.55.0.jar"/>
           <zipfileset
-              src="${gwt.tools.lib}/htmlunit/htmlunit-2.19/htmlunit-core-js-2.15.jar"/>
-          <zipfileset src="${gwt.tools.lib}/nekohtml/nekohtml-1.9.22.jar"/>
+              src="${gwt.tools.lib}/htmlunit/htmlunit-2.55.0/htmlunit-core-js-2.55.0.jar"/>
+          <zipfileset src="${gwt.tools.lib}/htmlunit/htmlunit-2.55.0/neko-htmlunit-2.55.0.jar"/>
+          <zipfileset src="${gwt.tools.lib}/htmlunit/htmlunit-2.55.0/salvation2-3.0.0.jar"/>
           <zipfileset src="${gwt.tools.lib}/cup/java-cup-11a.jar"/>
           <zipfileset src="${gwt.tools.lib}/xalan/xalan-2.7.1-nocup.jar"/>
           <zipfileset src="${gwt.tools.lib}/xerces/xerces-2_11_0/serializer-2.7.1.jar"/>
           <zipfileset src="${gwt.tools.lib}/xerces/xerces-2_11_0/xercesImpl-2.11.0.jar"/>
           <zipfileset src="${gwt.tools.lib}/xerces/xerces-2_11_0/xml-apis-1.4.01.jar"/>
           <zipfileset src="${gwt.tools.lib}/w3c/sac/sac-1.3.jar"/>
+          <zipfileset src="${gwt.tools.lib}/brotli/dec-0.1.2.jar"/>
           <!-- htmlunit dependencies not already included: END -->
           <zipfileset src="${gwt.tools.lib}/json/android-sdk-19.1/json-android-rebased.jar"/>
         </gwt.jar>
@@ -226,9 +236,9 @@
       <classpath>
         <pathelement location="${gwt.tools.lib}/apache/ant-zipscanner/ant-zipscanner-1.6.5-1-rebased.jar"/>
         <pathelement location="${gwt.tools.lib}/colt/colt-1.2.jar"/>
-        <pathelement location="${gwt.tools.lib}/objectweb/asm-7.1/asm-7.1.jar"/>
-        <pathelement location="${gwt.tools.lib}/objectweb/asm-7.1/asm-commons-7.1.jar"/>
-        <pathelement location="${gwt.tools.lib}/objectweb/asm-7.1/asm-util-7.1.jar"/>
+        <pathelement location="${gwt.tools.lib}/objectweb/asm-9.2/asm-9.2.jar"/>
+        <pathelement location="${gwt.tools.lib}/objectweb/asm-9.2/asm-commons-9.2.jar"/>
+        <pathelement location="${gwt.tools.lib}/objectweb/asm-9.2/asm-util-9.2.jar"/>
         <pathelement
             location="${gwt.tools.lib}/apache/commons/commons-collections-3.2.2.jar"/>
         <pathelement
diff --git a/dev/codeserver/java/com/google/gwt/dev/codeserver/WebServer.java b/dev/codeserver/java/com/google/gwt/dev/codeserver/WebServer.java
index 2b91969..d6b333a 100644
--- a/dev/codeserver/java/com/google/gwt/dev/codeserver/WebServer.java
+++ b/dev/codeserver/java/com/google/gwt/dev/codeserver/WebServer.java
@@ -123,7 +123,6 @@
     connector.setHost(bindAddress);
     connector.setPort(port);
     connector.setReuseAddress(false);
-    connector.setSoLingerTime(0);
     newServer.addConnector(connector);
 
     ServletContextHandler newHandler = new ServletContextHandler(ServletContextHandler.SESSIONS);
diff --git a/dev/core/src/com/google/gwt/dev/shell/HostedModePluginObject.java b/dev/core/src/com/google/gwt/dev/shell/HostedModePluginObject.java
index 68af427..98d5051 100644
--- a/dev/core/src/com/google/gwt/dev/shell/HostedModePluginObject.java
+++ b/dev/core/src/com/google/gwt/dev/shell/HostedModePluginObject.java
@@ -17,9 +17,9 @@
 
 import com.google.gwt.core.ext.TreeLogger;
 
+import com.gargoylesoftware.htmlunit.WebClient;
 import com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine;
 import com.gargoylesoftware.htmlunit.javascript.host.Window;
-import com.gargoylesoftware.htmlunit.javascript.host.WindowProxy;
 
 import net.sourceforge.htmlunit.corejs.javascript.Context;
 import net.sourceforge.htmlunit.corejs.javascript.Function;
@@ -27,6 +27,7 @@
 import net.sourceforge.htmlunit.corejs.javascript.ScriptableObject;
 
 import java.io.IOException;
+import java.util.Collections;
 
 /**
  * HTMLUnit object that represents the hosted-mode plugin.
@@ -122,11 +123,10 @@
             + " init: expected 1, got " + args.length);
       }
       try {
-        window = ((WindowProxy) args[0]).getDelegee();
+        window = (Window) args[0];
         return init(VERSION);
       } catch (ClassCastException e) {
-        throw Context.reportRuntimeError("Incorrect parameter types for "
-            + " initt: expected String");
+        throw Context.reportRuntimeError("Incorrect parameter types for init: expected Window");
       }
     }
 
@@ -149,6 +149,7 @@
   private Scriptable initMethod;
   private Window window;
   private final JavaScriptEngine jsEngine;
+  private final WebClient webClient;
   private final TreeLogger logger;
 
   private BrowserChannelClient browserChannelClient;
@@ -157,9 +158,12 @@
    * Creates a HostedModePluginObject with the passed-in JavaScriptEngine.
    *
    * @param jsEngine The JavaScriptEngine.
+   * @param webClient The WebClient being tested.
+   * @param logger A logger instance to notify the user of errors.
    */
-  public HostedModePluginObject(JavaScriptEngine jsEngine, TreeLogger logger) {
+  public HostedModePluginObject(JavaScriptEngine jsEngine, WebClient webClient, TreeLogger logger) {
     this.jsEngine = jsEngine;
+    this.webClient = webClient;
     this.logger = logger;
   }
 
@@ -184,9 +188,17 @@
     }
     // TODO: add whitelist and default-port support?
 
+    // We know that legacy dev mode is running, we need to tell HtmlUnit that it is safe
+    // to permit plain Java objects to leak into JS - the JavaObject type will return a
+    // Object[] with a success boolean and a value, and HtmlUnit will guard against this.
+    // The simplest way to do that here is to mark java.lang.Object as the java equivalent
+    // of some JS type - the name of the type doesn't matter.
+    webClient.setActiveXObjectMap(Collections.singletonMap(
+            "GwtLegacyDevModeExceptionOrReturnValue", "java.lang.Object"));
+
     try {
       HtmlUnitSessionHandler htmlUnitSessionHandler = new HtmlUnitSessionHandler(
-          window, jsEngine);
+          window, jsEngine, webClient);
       browserChannelClient = new BrowserChannelClient(addressParts, url,
           sessionKey, module, version, htmlUnitSessionHandler);
       htmlUnitSessionHandler.setSessionData(new SessionData(
diff --git a/dev/core/src/com/google/gwt/dev/shell/HtmlUnitSessionHandler.java b/dev/core/src/com/google/gwt/dev/shell/HtmlUnitSessionHandler.java
index 81cc71c..75abb3a 100644
--- a/dev/core/src/com/google/gwt/dev/shell/HtmlUnitSessionHandler.java
+++ b/dev/core/src/com/google/gwt/dev/shell/HtmlUnitSessionHandler.java
@@ -25,6 +25,7 @@
 
 import com.gargoylesoftware.htmlunit.ScriptException;
 import com.gargoylesoftware.htmlunit.ScriptResult;
+import com.gargoylesoftware.htmlunit.WebClient;
 import com.gargoylesoftware.htmlunit.WebWindow;
 import com.gargoylesoftware.htmlunit.html.HtmlPage;
 import com.gargoylesoftware.htmlunit.javascript.JavaScriptEngine;
@@ -108,9 +109,11 @@
   private final ToStringMethod toStringMethod = new ToStringMethod();
 
   private final Window window;
+  private final WebClient webClient;
 
-  HtmlUnitSessionHandler(Window window, JavaScriptEngine jsEngine) {
+  HtmlUnitSessionHandler(Window window, JavaScriptEngine jsEngine, WebClient webClient) {
     this.window = window;
+    this.webClient = webClient;
     logger.setMaxDetail(TreeLogger.ERROR);
     this.jsEngine = jsEngine;
     htmlPage = (HtmlPage) this.window.getWebWindow().getEnclosedPage();
@@ -161,7 +164,7 @@
   @Override
   public String getUserAgent() {
     return "HtmlUnit-"
-        + jsEngine.getWebClient().getBrowserVersion().getUserAgent();
+        + webClient.getBrowserVersion().getUserAgent();
   }
 
   @SuppressWarnings("unchecked")
@@ -286,6 +289,15 @@
       return returnVal;
     }
     if (value instanceof Scriptable) {
+      if (value instanceof SimpleScriptableProxy) {
+        // HtmlUnit will return proxies to java for the window/document objects,
+        // so that those objects can work after navigating away from the page.
+        // However, GWTTestCase operates inside a single page session, so we
+        // can unwrap these proxies to get the real instance. Without doing
+        // this, the refToJsObject mapping would indicate that an object might
+        // not equal itself
+        value = ((SimpleScriptableProxy<?>) value).getDelegee();
+      }
       if (value instanceof ScriptableObject) {
         /*
          * HACK: check for native types like NativeString. NativeString is
diff --git a/dev/core/src/com/google/gwt/dev/shell/jetty/JettyLauncher.java b/dev/core/src/com/google/gwt/dev/shell/jetty/JettyLauncher.java
index fcfe5d3..9c1475c 100644
--- a/dev/core/src/com/google/gwt/dev/shell/jetty/JettyLauncher.java
+++ b/dev/core/src/com/google/gwt/dev/shell/jetty/JettyLauncher.java
@@ -26,6 +26,7 @@
 
 import org.eclipse.jetty.http.HttpField;
 import org.eclipse.jetty.http.HttpFields;
+import org.eclipse.jetty.security.ConstraintSecurityHandler;
 import org.eclipse.jetty.server.HttpConfiguration;
 import org.eclipse.jetty.server.HttpConnectionFactory;
 import org.eclipse.jetty.server.Request;
@@ -36,6 +37,8 @@
 import org.eclipse.jetty.server.ServerConnector;
 import org.eclipse.jetty.server.SslConnectionFactory;
 import org.eclipse.jetty.server.handler.RequestLogHandler;
+import org.eclipse.jetty.servlet.ErrorPageErrorHandler;
+import org.eclipse.jetty.servlet.ServletContextHandler;
 import org.eclipse.jetty.util.component.AbstractLifeCycle;
 import org.eclipse.jetty.util.log.Log;
 import org.eclipse.jetty.util.log.Logger;
@@ -127,7 +130,7 @@
       }
       if (logger.isLoggable(logStatus)) {
         TreeLogger branch = logger.branch(logStatus, String.valueOf(status)
-            + " - " + request.getMethod() + ' ' + request.getUri() + " ("
+            + " - " + request.getMethod() + ' ' + request.getRequestURI() + " ("
             + userString + request.getRemoteHost() + ')' + bytesString);
         if (branch.isLoggable(logHeaders)) {
           logHeaders(branch.branch(logHeaders, "Request headers"), logHeaders,
@@ -350,6 +353,7 @@
       private final ClasspathPattern systemClassesFromWebappFirst = new ClasspathPattern(new String[] {
           "-javax.servlet.",
           "-javax.el.",
+          "-javax.websocket.",
           "javax.",
       });
       private final ClasspathPattern allowedFromSystemClassLoader = new ClasspathPattern(new String[] {
@@ -371,11 +375,13 @@
 
       @Override
       public Enumeration<URL> getResources(String name) throws IOException {
-        // Logic copied from Jetty's WebAppClassLoader
-        List<URL> fromParent = isServerClass(name)
+        // Logic copied from Jetty's WebAppClassLoader, modified to use the system classloader
+        // instead of the parent classloader for server classes
+        List<URL> fromParent = WebAppContextWithReload.this.isServerClass(name)
             ? Collections.<URL>emptyList()
             : Lists.newArrayList(Iterators.forEnumeration(systemClassLoader.getResources(name)));
-        Iterator<URL> fromWebapp = isSystemClass(name) && !fromParent.isEmpty()
+        Iterator<URL> fromWebapp = WebAppContextWithReload.this.isSystemClass(name)
+                && !fromParent.isEmpty()
             ? Collections.<URL>emptyIterator()
             : Iterators.forEnumeration(findResources(name));
         return Iterators.asEnumeration(Iterators.concat(fromWebapp, fromParent.iterator()));
@@ -394,7 +400,8 @@
         // Note: bootstrap has already been searched, so javax. classes should be
         // tried from the webapp first (except for javax.servlet and javax.el).
         URL found;
-        if (isSystemClass(checkName) && !systemClassesFromWebappFirst.match(checkName)) {
+        if (WebAppContextWithReload.this.isSystemClass(checkName)
+                && !systemClassesFromWebappFirst.match(checkName)) {
           found = systemClassLoader.getResource(name);
           if (found != null) {
             return found;
@@ -409,7 +416,7 @@
 
         // See if the outside world has it.
         found = systemClassLoader.getResource(name);
-        if (found == null || isServerClass(checkName)) {
+        if (found == null || WebAppContextWithReload.this.isServerClass(checkName)) {
           return null;
         }
 
@@ -431,22 +438,27 @@
       }
 
       @Override
-      protected Class<?> findClass(String name) throws ClassNotFoundException {
+      protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
         // For system path, always prefer the outside world.
         // Note: bootstrap has already been searched, so javax. classes should be
         // tried from the webapp first (except for javax.servlet).
-        if (isSystemClass(name) && !systemClassesFromWebappFirst.match(name)) {
+        if (WebAppContextWithReload.this.isSystemClass(name)
+                && !systemClassesFromWebappFirst.match(name)) {
           try {
-            return systemClassLoader.loadClass(name);
+            Class<?> loaded = systemClassLoader.loadClass(name);
+            if (resolve) {
+              resolveClass(loaded);
+            }
+            return loaded;
           } catch (ClassNotFoundException e) {
           }
         }
 
         try {
-          return super.findClass(name);
+          return super.loadClass(name, resolve);
         } catch (ClassNotFoundException e) {
           // Don't allow server classes to be loaded from the outside.
-          if (isServerClass(name)) {
+          if (WebAppContextWithReload.this.isServerClass(name)) {
             throw e;
           }
         }
@@ -455,7 +467,7 @@
         String resourceName = name.replace('.', '/') + ".class";
         URL found = systemClassLoader.getResource(resourceName);
         if (found == null) {
-          return null;
+          throw new ClassNotFoundException(name);
         }
 
         // Special-case JDBCUnloader; it should always be loaded in the webapp classloader
@@ -467,17 +479,21 @@
         // Those classes are allowed to be loaded right from the systemClassLoader
         // Note: Jetty classes here are not "server classes", handled above.
         if (allowedFromSystemClassLoader.match(name)) {
-          return systemClassLoader.loadClass(name);
+          Class<?> loaded = systemClassLoader.loadClass(name);
+          if (resolve) {
+            resolveClass(loaded);
+          }
+          return loaded;
         }
 
         // Warn, add containing URL to our own ClassLoader, and retry the call.
         String warnMessage = "Server class '"
-            + name
-            + "' could not be found in the web app, but was found on the system classpath";
+                + name
+                + "' could not be found in the web app, but was found on the system classpath";
         if (!addContainingClassPathEntry(warnMessage, found, resourceName)) {
           throw new ClassNotFoundException(name);
         }
-        return super.findClass(name);
+        return super.loadClass(name, resolve);
       }
 
       private boolean addContainingClassPathEntry(String warnMessage,
@@ -533,7 +549,9 @@
 
     private WebAppContextWithReload(TreeLogger logger, String webApp,
         String contextPath) {
-      super(webApp, contextPath);
+      super(null, contextPath, null, null, null, new ErrorPageErrorHandler(),
+              ServletContextHandler.SESSIONS);
+      this.setWar(webApp);
       this.logger = logger;
 
       // Prevent file locking on Windows; pick up file changes.
@@ -594,9 +612,6 @@
 
     // Allow binding to a port even if it's still in state TIME_WAIT.
     connector.setReuseAddress(true);
-
-    // Linux keeps the port blocked after shutdown if we don't disable this.
-    connector.setSoLingerTime(0);
   }
 
   // default value used if setBaseLogLevel isn't called
@@ -751,7 +766,8 @@
     }
 
     // Create a new web app in the war directory.
-      WebAppContext wac = createWebAppContext(logger, appRootDir);
+    WebAppContext wac = createWebAppContext(logger, appRootDir);
+    wac.setSecurityHandler(new ConstraintSecurityHandler());
 
     RequestLogHandler logHandler = new RequestLogHandler();
     logHandler.setRequestLog(new JettyRequestLogger(logger, getBaseLogLevel()));
diff --git a/dev/core/test/com/google/gwt/core/ext/linker/impl/SelectionScriptJavaScriptTest.java b/dev/core/test/com/google/gwt/core/ext/linker/impl/SelectionScriptJavaScriptTest.java
index 6b67e7e..b022cdb 100644
--- a/dev/core/test/com/google/gwt/core/ext/linker/impl/SelectionScriptJavaScriptTest.java
+++ b/dev/core/test/com/google/gwt/core/ext/linker/impl/SelectionScriptJavaScriptTest.java
@@ -265,6 +265,10 @@
     webConnection.setResponse(new URL(
         "http://foo.test/foo/test.Module.nocache.js"), testScript.toString(),
         "application/javascript");
+    webConnection.setResponse(new URL(
+            "http://foo.test/from/nocache/__MODULE_NAME__.nocache.js"),
+            testScript.toString(),
+            "application/javascript");
     webClient.setWebConnection(webConnection);
 
     final List<String> alerts = new ArrayList<String>();
diff --git a/maven/poms/gwt/pom-template.xml b/maven/poms/gwt/pom-template.xml
index 3bd4042..f4bae17 100644
--- a/maven/poms/gwt/pom-template.xml
+++ b/maven/poms/gwt/pom-template.xml
@@ -21,8 +21,8 @@
         </license>
     </licenses>
     <properties>
-      <jetty.version>9.2.14.v20151106</jetty.version>
-      <asm.version>7.1</asm.version>
+      <jetty.version>9.4.44.v20210927</jetty.version>
+      <asm.version>9.2</asm.version>
     </properties>
     <dependencyManagement>
         <dependencies>
@@ -118,7 +118,7 @@
             <dependency>
                 <groupId>net.sourceforge.htmlunit</groupId>
                 <artifactId>htmlunit</artifactId>
-                <version>2.19</version>
+                <version>2.55.0</version>
             </dependency>
             <dependency>
                 <groupId>org.w3c.css</groupId>
diff --git a/user/src/com/google/gwt/dom/client/DOMImplMozilla.java b/user/src/com/google/gwt/dom/client/DOMImplMozilla.java
index c582597..100d7d0 100644
--- a/user/src/com/google/gwt/dom/client/DOMImplMozilla.java
+++ b/user/src/com/google/gwt/dom/client/DOMImplMozilla.java
@@ -233,6 +233,18 @@
   private native NativeEvent createKeyEventImpl(Document doc, String type,
       boolean canBubble, boolean cancelable, boolean ctrlKey, boolean altKey,
       boolean shiftKey, boolean metaKey, int keyCode, int charCode) /*-{
+    if (!!window.KeyboardEvent) {
+      return new KeyboardEvent(type, {
+        ctrlKey: ctrlKey,
+        altKey: altKey,
+        shiftKey: shiftKey,
+        metaKey: metaKey,
+        keyCode: keyCode,
+        charCode: charCode,
+        bubbles: canBubble,
+        cancelable: cancelable
+      });
+    }
     var evt = doc.createEvent('KeyboardEvent');
     if (evt.initKeyEvent) {
       // Gecko
diff --git a/user/src/com/google/gwt/junit/RunStyleHtmlUnit.java b/user/src/com/google/gwt/junit/RunStyleHtmlUnit.java
index 133c848..7381542 100644
--- a/user/src/com/google/gwt/junit/RunStyleHtmlUnit.java
+++ b/user/src/com/google/gwt/junit/RunStyleHtmlUnit.java
@@ -15,8 +15,6 @@
  */
 package com.google.gwt.junit;
 
-import static com.gargoylesoftware.htmlunit.BrowserVersionFeatures.JS_WINDOW_ONERROR_COLUMN_ERROR_ARGUMENT;
-
 import com.google.gwt.core.ext.TreeLogger;
 import com.google.gwt.dev.shell.HostedModePluginObject;
 import com.google.gwt.thirdparty.guava.common.collect.ImmutableSet;
@@ -26,7 +24,6 @@
 import com.gargoylesoftware.htmlunit.BrowserVersion;
 import com.gargoylesoftware.htmlunit.FailingHttpStatusCodeException;
 import com.gargoylesoftware.htmlunit.IncorrectnessListener;
-import com.gargoylesoftware.htmlunit.InteractivePage;
 import com.gargoylesoftware.htmlunit.OnbeforeunloadHandler;
 import com.gargoylesoftware.htmlunit.Page;
 import com.gargoylesoftware.htmlunit.ScriptException;
@@ -116,21 +113,30 @@
       webClient.setJavaScriptErrorListener(new JavaScriptErrorListener() {
 
         @Override
-        public void loadScriptError(InteractivePage htmlPage, URL scriptUrl,
+        public void loadScriptError(HtmlPage htmlPage, URL scriptUrl,
             Exception exception) {
             treeLogger.log(TreeLogger.ERROR,
               "Load Script Error: " + exception, exception);
         }
 
         @Override
-        public void malformedScriptURL(InteractivePage htmlPage, String url,
+        public void warn(String message, String sourceName, int line,
+                         String lineSource, int lineOffset) {
+            treeLogger.log(TreeLogger.WARN, "Script Warning: " + message +
+                    ", sourceName=" + sourceName + ", line=" + line + ", lineSource=" +
+                    lineSource + ", lineOffset=" + lineOffset
+            );
+        }
+
+        @Override
+        public void malformedScriptURL(HtmlPage htmlPage, String url,
             MalformedURLException malformedURLException) {
           treeLogger.log(TreeLogger.ERROR,
               "Malformed Script URL: " + malformedURLException.getLocalizedMessage());
         }
 
         @Override
-        public void scriptException(InteractivePage htmlPage,
+        public void scriptException(HtmlPage htmlPage,
             ScriptException scriptException) {
           treeLogger.log(TreeLogger.DEBUG,
               "Script Exception: " + scriptException.getLocalizedMessage() +
@@ -138,7 +144,7 @@
         }
 
         @Override
-        public void timeoutError(InteractivePage htmlPage, long allowedTime,
+        public void timeoutError(HtmlPage htmlPage, long allowedTime,
             long executionTime) {
           treeLogger.log(TreeLogger.ERROR,
               "Script Timeout Error " + executionTime + " > " + allowedTime);
@@ -188,20 +194,22 @@
   private static class HostedJavaScriptEngine extends JavaScriptEngine {
 
     private static final long serialVersionUID = 3594816610842448691L;
+    private final WebClient webClient;
     private final TreeLogger logger;
 
     public HostedJavaScriptEngine(WebClient webClient, TreeLogger logger) {
       super(webClient);
+      this.webClient = webClient;
       this.logger = logger;
     }
 
     @Override
-    public void initialize(WebWindow webWindow) {
+    public void initialize(WebWindow webWindow, Page page) {
       // Hook in the hosted-mode plugin after initializing the JS engine.
-      super.initialize(webWindow);
+      super.initialize(webWindow, page);
       Window window = (Window) webWindow.getScriptableObject();
       window.defineProperty("__gwt_HostedModePlugin",
-          new HostedModePluginObject(this, logger), ScriptableObject.READONLY);
+          new HostedModePluginObject(this, webClient, logger), ScriptableObject.READONLY);
     }
   }
 
@@ -213,9 +221,11 @@
    */
   private static class WebJavaScriptEngine extends JavaScriptEngine {
     private static final Log LOG = LogFactory.getLog(JavaScriptEngine.class);
+    private final WebClient webClient;
 
     public WebJavaScriptEngine(WebClient webClient) {
       super(webClient);
+      this.webClient = webClient;
     }
 
     @Override
@@ -225,7 +235,7 @@
       // instead of Window's triggerOnError.
 
       // Trigger window.onerror, if it has been set.
-      final InteractivePage page = scriptException.getPage();
+      final HtmlPage page = scriptException.getPage();
       if (triggerOnError && page != null) {
         final WebWindow window = page.getEnclosingWindow();
         if (window != null) {
@@ -240,12 +250,12 @@
         }
       }
       final JavaScriptErrorListener javaScriptErrorListener =
-          getWebClient().getJavaScriptErrorListener();
+              webClient.getJavaScriptErrorListener();
       if (javaScriptErrorListener != null) {
         javaScriptErrorListener.scriptException(page, scriptException);
       }
       // Throw a Java exception if the user wants us to.
-      if (getWebClient().getOptions().isThrowExceptionOnScriptError()) {
+      if (webClient.getOptions().isThrowExceptionOnScriptError()) {
         throw scriptException;
       }
       // Log the error; ScriptException instances provide good debug info.
@@ -262,19 +272,15 @@
         final String url = e.getPage().getUrl().toExternalForm();
         final int line = e.getFailingLineNumber();
 
-        Object[] args;
-        if (w.getBrowserVersion().hasFeature(JS_WINDOW_ONERROR_COLUMN_ERROR_ARGUMENT)) {
-          final int column = e.getFailingColumnNumber();
+        final int column = e.getFailingColumnNumber();
 
-          Object jsError = null;
-          if (e.getCause() instanceof JavaScriptException) {
-            jsError = ((JavaScriptException) e.getCause()).getValue();
-          }
-
-          args = new Object[] {msg, url, Integer.valueOf(line), Integer.valueOf(column), jsError};
-        } else {
-          args = new Object[] {msg, url, Integer.valueOf(line)};
+        Object jsError = null;
+        if (e.getCause() instanceof JavaScriptException) {
+          jsError = ((JavaScriptException) e.getCause()).getValue();
         }
+
+        Object[] args = new Object[]{msg, url, line, column, jsError};
+
         f.call(Context.getCurrentContext(), w, w, args);
       }
     }
@@ -286,9 +292,9 @@
   static {
     // “Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.71 Safari/537.36 Edge/12.0″
     addBrowser(BrowserVersion.EDGE, "safari");
-    addBrowser(BrowserVersion.FIREFOX_38, "gecko1_8");
+    addBrowser(BrowserVersion.FIREFOX, "gecko1_8");
     addBrowser(BrowserVersion.CHROME, "safari");
-    addBrowser(BrowserVersion.INTERNET_EXPLORER_11, "gecko1_8");
+    addBrowser(BrowserVersion.INTERNET_EXPLORER, "gecko1_8");
   }
 
   private static void addBrowser(BrowserVersion browser, String userAgent) {
@@ -324,8 +330,8 @@
   @Override
   public int initialize(String args) {
     if (args == null || args.length() == 0) {
-      // If no browsers specified, default to Firefox 38.
-      args = "FF38";
+      // If no browsers specified, default to Firefox.
+      args = "FF";
     }
     Set<BrowserVersion> browserSet = new HashSet<BrowserVersion>();
     Set<String> userAgentSet = new HashSet<String>();
diff --git a/user/test/com/google/gwt/core/client/impl/StackTraceNativeTest.java b/user/test/com/google/gwt/core/client/impl/StackTraceNativeTest.java
index 576eb0d..1a6cd35 100644
--- a/user/test/com/google/gwt/core/client/impl/StackTraceNativeTest.java
+++ b/user/test/com/google/gwt/core/client/impl/StackTraceNativeTest.java
@@ -105,9 +105,6 @@
         ? limited_wrap : (thrown != TYPE_ERROR ? limited_fillInStackTrace : full);
   }
 
-  // TODO(goktug): new Error().stack is broken for htmlunit:
-  // https://sourceforge.net/p/htmlunit/bugs/1606/
-  @DoNotRunWith(Platform.HtmlUnitBug)
   public void testCollectorType() {
     if (isSafari5()) {
       assertTrue(isLegacyCollector());
diff --git a/user/test/com/google/gwt/dom/client/NodeTest.java b/user/test/com/google/gwt/dom/client/NodeTest.java
index 54df1a9..5e70c65 100644
--- a/user/test/com/google/gwt/dom/client/NodeTest.java
+++ b/user/test/com/google/gwt/dom/client/NodeTest.java
@@ -16,8 +16,6 @@
 package com.google.gwt.dom.client;
 
 import com.google.gwt.core.client.JavaScriptObject;
-import com.google.gwt.junit.DoNotRunWith;
-import com.google.gwt.junit.Platform;
 import com.google.gwt.junit.client.GWTTestCase;
 
 import java.util.Locale;
@@ -266,7 +264,6 @@
   /**
    * ownerDocument.
    */
-  @DoNotRunWith(Platform.HtmlUnitBug)
   public void testOwnerDocument() {
     Document doc = Document.get();
     BodyElement body = doc.getBody();
diff --git a/user/test/com/google/gwt/emultest/java/lang/SystemTest.java b/user/test/com/google/gwt/emultest/java/lang/SystemTest.java
index 33f7379..951b412 100644
--- a/user/test/com/google/gwt/emultest/java/lang/SystemTest.java
+++ b/user/test/com/google/gwt/emultest/java/lang/SystemTest.java
@@ -15,9 +15,6 @@
  */
 package com.google.gwt.emultest.java.lang;
 
-import static com.google.gwt.junit.Platform.HtmlUnitBug;
-
-import com.google.gwt.junit.DoNotRunWith;
 import com.google.gwt.junit.client.GWTTestCase;
 import com.google.gwt.testing.TestUtils;
 
@@ -328,7 +325,6 @@
     assertEquals("default", System.getProperty("otherNonExistent", someConf));
   }
 
-  @DoNotRunWith({HtmlUnitBug})
   public void testNanoTime() {
     assertTrue(System.nanoTime() > 0);
   }
diff --git a/user/test/com/google/gwt/jsonp/client/JsonpRequestTest.java b/user/test/com/google/gwt/jsonp/client/JsonpRequestTest.java
index 7817583..a3d59da 100644
--- a/user/test/com/google/gwt/jsonp/client/JsonpRequestTest.java
+++ b/user/test/com/google/gwt/jsonp/client/JsonpRequestTest.java
@@ -223,19 +223,13 @@
         new AssertFailureCallback<String>("ERROR"));
   }
 
-  /**
-   * Hangs indefinitely in devmode with HtmlUnit.
-   * <p>
-   * Call occurs through postponedActions in HtmlUnit that execute
-   * synchronously. Should be async. Need to file HtmlUnitBug.
-   */
-  @DoNotRunWith(Platform.HtmlUnitBug)
   public void testIds() {
     delayTestFinish(RESPONSE_DELAY);
+    Counter counter = new Counter(2);
     JsonpRequest<String> reqA = jsonp.requestString(echo("'A'"),
-        new AssertSuccessCallback<String>("A"));
+        new AssertSuccessCallback<String>("A", counter));
     JsonpRequest<String> reqB = jsonp.requestString(echo("'B'"),
-        new AssertSuccessCallback<String>("B"));
+        new AssertSuccessCallback<String>("B", counter));
     // WARNING: knows the current structure of IDs
     int idA = Integer.parseInt(reqA.getCallbackId().substring(1));
     int idB = Integer.parseInt(reqB.getCallbackId().substring(1));
diff --git a/user/test/com/google/gwt/junit/client/CspTest.java b/user/test/com/google/gwt/junit/client/CspTest.java
index f078ee1..d0db547 100644
--- a/user/test/com/google/gwt/junit/client/CspTest.java
+++ b/user/test/com/google/gwt/junit/client/CspTest.java
@@ -31,7 +31,7 @@
     return "com.google.gwt.junit.JUnitTest";
   }
 
-  @DoNotRunWith(Platform.HtmlUnitLayout)
+  @DoNotRunWith(Platform.HtmlUnitBug)
   public void testCsp() {
     initClickDidFire();
 
diff --git a/user/test/com/google/gwt/uibinder/test/client/UiBinderTest.java b/user/test/com/google/gwt/uibinder/test/client/UiBinderTest.java
index ddab38b..9ea8b15 100644
--- a/user/test/com/google/gwt/uibinder/test/client/UiBinderTest.java
+++ b/user/test/com/google/gwt/uibinder/test/client/UiBinderTest.java
@@ -20,8 +20,6 @@
 import com.google.gwt.dom.client.Element;
 import com.google.gwt.dom.client.ParagraphElement;
 import com.google.gwt.dom.client.SpanElement;
-import com.google.gwt.junit.DoNotRunWith;
-import com.google.gwt.junit.Platform;
 import com.google.gwt.junit.client.GWTTestCase;
 import com.google.gwt.resources.client.ClientBundle;
 import com.google.gwt.resources.client.CssResource.NotStrict;
@@ -554,12 +552,6 @@
     assertEquals("funny characters \\ \" ' ' & < > > { }", t);
   }
 
-  /**
-   * Fails in all modes due to an HtmlUnit bug: offsetWidth always returns 1256.
-   * TODO(t.broyer): file a new HtmlUnit bug.
-   * Similar to http://sourceforge.net/p/htmlunit/bugs/1447/
-   */
-  @DoNotRunWith(Platform.HtmlUnitBug)
   public void testCustomImageClass() {
     ImageResource resource = widgetUi.prettyImage;
     Image widget = widgetUi.fooImage;
@@ -569,12 +561,6 @@
     assertEquals(resource.getLeft(), widget.getOriginLeft());
   }
 
-  /**
-   * Fails in all modes due to an HtmlUnit bug: offsetWidth always returns 1256.
-   * TODO(t.broyer): file a new HtmlUnit bug.
-   * Similar to http://sourceforge.net/p/htmlunit/bugs/1447/
-   */
-  @DoNotRunWith(Platform.HtmlUnitBug)
   public void testImageResourceInImageWidget() {
     ImageResource resource = widgetUi.prettyImage;
     Image widget = widgetUi.babyWidget;
diff --git a/user/test/com/google/gwt/user/client/ui/CreateEventTest.java b/user/test/com/google/gwt/user/client/ui/CreateEventTest.java
index 262223a..387feef 100644
--- a/user/test/com/google/gwt/user/client/ui/CreateEventTest.java
+++ b/user/test/com/google/gwt/user/client/ui/CreateEventTest.java
@@ -467,14 +467,6 @@
     assertTrue("Expected parent to receive event", listener.parentReceived);
   }
 
-  /**
-   * Tests createErrorEvent().
-   *
-   * Failed in all modes due to HtmlUnit bug:
-   * https://sourceforge.net/tracker/?func
-   * =detail&aid=2888342&group_id=47038&atid=448266
-   */
-  @DoNotRunWith({Platform.HtmlUnitBug})
   public void testTriggerErrorEvent() {
     ImgEventListener listener = new ImgEventListener("error");
     Event.setEventListener(parent, listener);
@@ -686,12 +678,6 @@
     listener.cancel();
   }
 
-  /**
-   * Tests createKeyPressEvent().
-   *
-   * Failed in all modes due to HtmlUnit bug:
-   */
-  @DoNotRunWith({Platform.HtmlUnitBug})
   public void testTriggerScrollEvent() {
     NonBubbleAssertingEventListener listener = new NonBubbleAssertingEventListener(
         "scroll") {
diff --git a/user/test/com/google/gwt/user/client/ui/HistoryTest.java b/user/test/com/google/gwt/user/client/ui/HistoryTest.java
index e3ea748..5df0b7f 100644
--- a/user/test/com/google/gwt/user/client/ui/HistoryTest.java
+++ b/user/test/com/google/gwt/user/client/ui/HistoryTest.java
@@ -414,12 +414,6 @@
     timer.schedule(200);
   }
 
-  /*
-   * HtmlUnit reports:
-   *   expected=abc;,/?:@&=+$-_.!~*()ABC123foo
-   *   actual  =abc;,/?:@&=%20$-_.!~*()ABC123foo
-   */
-  @DoNotRunWith(Platform.HtmlUnitBug)
   public void testTokenNonescaping() {
     final String shouldNotChange = "abc;,/?:@&=+$-_.!~*()ABC123foo";
 
diff --git a/user/test/com/google/gwt/user/client/ui/MenuBarTest.java b/user/test/com/google/gwt/user/client/ui/MenuBarTest.java
index 27bf0c8..862b6c9 100644
--- a/user/test/com/google/gwt/user/client/ui/MenuBarTest.java
+++ b/user/test/com/google/gwt/user/client/ui/MenuBarTest.java
@@ -21,8 +21,6 @@
 import com.google.gwt.dom.client.Element;
 import com.google.gwt.dom.client.NativeEvent;
 import com.google.gwt.event.dom.client.KeyCodes;
-import com.google.gwt.junit.DoNotRunWith;
-import com.google.gwt.junit.Platform;
 import com.google.gwt.safehtml.shared.SafeHtmlUtils;
 import com.google.gwt.user.client.Command;
 
@@ -216,7 +214,6 @@
     assertNull(l2.getPopup());
   }
 
-  @DoNotRunWith({Platform.HtmlUnitBug})
   public void testBlur() {
     // Create a menu bar with children.
     final MenuBar menu = new MenuBar();
@@ -234,7 +231,6 @@
     assertNull(menu.getSelectedItem());
   }
 
-  @DoNotRunWith({Platform.HtmlUnitBug})
   public void testSetFocusOnHoverEnabled() {
     delayTestFinish(1000);
     TextBox focusOwner = new TextBox();
diff --git a/user/test/com/google/gwt/user/client/ui/PopupTest.java b/user/test/com/google/gwt/user/client/ui/PopupTest.java
index d0738a4..16984bc 100644
--- a/user/test/com/google/gwt/user/client/ui/PopupTest.java
+++ b/user/test/com/google/gwt/user/client/ui/PopupTest.java
@@ -20,6 +20,8 @@
 import com.google.gwt.dom.client.Element;
 import com.google.gwt.event.logical.shared.CloseEvent;
 import com.google.gwt.event.logical.shared.CloseHandler;
+import com.google.gwt.junit.DoNotRunWith;
+import com.google.gwt.junit.Platform;
 import com.google.gwt.junit.client.GWTTestCase;
 import com.google.gwt.user.client.History;
 import com.google.gwt.user.client.Timer;
@@ -145,7 +147,11 @@
   /**
    * Tests that a large PopupPanel is not positioned off the top or left edges
    * of the browser window, making part of the panel unreachable.
+   *
+   * <p>This test is broken in HtmlUnit 2.55.0, see
+   * https://github.com/HtmlUnit/htmlunit/issues/382.</p>
    */
+  @DoNotRunWith(Platform.HtmlUnitLayout)
   public void testCenterLargePopup() {
     PopupPanel popup = new PopupPanel();
     popup.setHeight("4096px");
@@ -318,6 +324,11 @@
     }
   }
 
+  /**
+   * This test is broken in HtmlUnit 2.55.0, see
+   * https://github.com/HtmlUnit/htmlunit/issues/382.
+   */
+  @DoNotRunWith(Platform.HtmlUnitLayout)
   public void testPopup() {
     // Get rid of window margins so we can test absolute position.
     Window.setMargin("0px");
diff --git a/user/test/com/google/gwt/user/client/ui/impl/ClippedImagePrototypeTest.java b/user/test/com/google/gwt/user/client/ui/impl/ClippedImagePrototypeTest.java
index 4d4d1d4..27eb267 100644
--- a/user/test/com/google/gwt/user/client/ui/impl/ClippedImagePrototypeTest.java
+++ b/user/test/com/google/gwt/user/client/ui/impl/ClippedImagePrototypeTest.java
@@ -19,8 +19,6 @@
 import com.google.gwt.event.dom.client.ErrorHandler;
 import com.google.gwt.event.dom.client.LoadEvent;
 import com.google.gwt.event.dom.client.LoadHandler;
-import com.google.gwt.junit.DoNotRunWith;
-import com.google.gwt.junit.Platform;
 import com.google.gwt.junit.client.GWTTestCase;
 import com.google.gwt.safehtml.shared.UriUtils;
 import com.google.gwt.user.client.Timer;
@@ -55,15 +53,6 @@
     return "com.google.gwt.user.UserTest";
   }
 
-  /**
-   * Tests that a clipped image can be transformed to match a given prototype.
-   * Also checks to make sure that a load event is fired on when
-   * {@link com.google.gwt.user.client.ui.impl.ClippedImagePrototype#applyTo(com.google.gwt.user.client.ui.Image)}
-   * is called.
-   *
-   * TODO(jlabanca): Enable this test when issue 863 is fixed
-   */
-  @DoNotRunWith({Platform.HtmlUnitBug})
   public void disabledTestApplyToClippedImage() {
     final Image image = new Image("counting-backwards.png", 12, 13, 8, 8);
 
diff --git a/user/test/com/google/gwt/xml/client/XMLTest.java b/user/test/com/google/gwt/xml/client/XMLTest.java
index 6a1396b..f349dd3 100644
--- a/user/test/com/google/gwt/xml/client/XMLTest.java
+++ b/user/test/com/google/gwt/xml/client/XMLTest.java
@@ -149,7 +149,6 @@
     assertEquals(de.getAttributeNode("unset"), null);
   }
 
-  @DoNotRunWith({Platform.HtmlUnitBug})
   public void testCreate() {
     Document d = XMLParser.createDocument();
     CDATASection createCDATA = d.createCDATASection("sampl<<< >>e data");
diff --git a/user/test/com/google/web/bindery/requestfactory/server/RequestFactoryTestServer.java b/user/test/com/google/web/bindery/requestfactory/server/RequestFactoryTestServer.java
index 0c9e3f2..a583d55 100644
--- a/user/test/com/google/web/bindery/requestfactory/server/RequestFactoryTestServer.java
+++ b/user/test/com/google/web/bindery/requestfactory/server/RequestFactoryTestServer.java
@@ -42,7 +42,7 @@
     handler.addFilter(GzipFilter.class, "/*", EnumSet.allOf(DispatcherType.class));
 
     SessionHandler sessionHandler = new SessionHandler();
-    sessionHandler.getSessionManager().setMaxInactiveInterval(5);
+    sessionHandler.setMaxInactiveInterval(5);
     handler.setSessionHandler(sessionHandler);
     server.setHandler(handler);