Remove deprecated use of isChecked in javadoc

fixes issue 6232

Change-Id: I40b0fd568ac2032627ac1710bfb35f6f1d966183
diff --git a/user/javadoc/com/google/gwt/examples/CheckBoxExample.java b/user/javadoc/com/google/gwt/examples/CheckBoxExample.java
index 9e5eab4..538b3d2 100644
--- a/user/javadoc/com/google/gwt/examples/CheckBoxExample.java
+++ b/user/javadoc/com/google/gwt/examples/CheckBoxExample.java
@@ -24,15 +24,17 @@
 
 public class CheckBoxExample implements EntryPoint {
 
+  @Override
   public void onModuleLoad() {
     // Make a new check box, and select it by default.
     CheckBox cb = new CheckBox("Foo");
-    cb.setChecked(true);
+    cb.setValue(true);
 
     // Hook up a handler to find out when it's clicked.
     cb.addClickHandler(new ClickHandler() {
+      @Override
       public void onClick(ClickEvent event) {
-        boolean checked = ((CheckBox) event.getSource()).isChecked();
+        boolean checked = ((CheckBox) event.getSource()).getValue();
         Window.alert("It is " + (checked ? "" : "not ") + "checked");
       }
     });