diff -r b1f8e0d263cc java.source/apichanges.xml
--- a/java.source/apichanges.xml	Mon Apr 02 11:33:38 2012 +0200
+++ b/java.source/apichanges.xml	Mon Apr 02 15:00:52 2012 +0200
@@ -108,6 +108,20 @@
     <!-- ACTUAL CHANGES BEGIN HERE: -->
 
     <changes>
+        <change id="WorkingCopy-resolveRewriteTarget">
+             <api name="general"/>
+             <summary>Added <code>WorkingCopy.resolveRewriteTarget</code>.</summary>
+             <version major="0" minor="101"/>
+             <date day="9" month="4" year="2012"/>
+             <author login="jlahoda"/>
+            <compatibility addition="yes" binary="compatible" deletion="no" deprecation="no" modification="no" semantic="compatible" source="compatible"/>
+             <description>
+                 Added a method<code>resolveRewriteTarget</code> to class <code>WorkingCopy</code>,
+                 that returns the tree into which the given tree has been rewritten.
+             </description>
+             <class package="org.netbeans.api.java.source" name="WorkingCopy"/>
+             <issue number="209375"/>
+        </change>
         <change id="GeneratorUtilities-appendToAnnotationValue">
              <api name="general"/>
              <summary>Added <code>GeneratorUtilities.appendToAnnotationValue</code>.</summary>
diff -r b1f8e0d263cc java.source/nbproject/project.properties
--- a/java.source/nbproject/project.properties	Mon Apr 02 11:33:38 2012 +0200
+++ b/java.source/nbproject/project.properties	Mon Apr 02 15:00:52 2012 +0200
@@ -46,7 +46,7 @@
 javadoc.title=Java Source
 javadoc.arch=${basedir}/arch.xml
 javadoc.apichanges=${basedir}/apichanges.xml
-spec.version.base=0.100.0
+spec.version.base=0.101.0
 test.qa-functional.cp.extra=${refactoring.java.dir}/modules/ext/javac-api-nb-7.0-b07.jar
 test.unit.run.cp.extra=${o.n.core.dir}/core/core.jar:\
     ${o.n.core.dir}/lib/boot.jar:\
diff -r b1f8e0d263cc java.source/src/org/netbeans/api/java/source/WorkingCopy.java
--- a/java.source/src/org/netbeans/api/java/source/WorkingCopy.java	Mon Apr 02 11:33:38 2012 +0200
+++ b/java.source/src/org/netbeans/api/java/source/WorkingCopy.java	Mon Apr 02 15:00:52 2012 +0200
@@ -295,6 +295,33 @@
     public synchronized void tag(@NonNull Tree t, @NonNull Object tag) {
         tree2Tag.put(t, tag);
     }
+
+    /**Returns the tree into which the given tree was rewritten using the
+     * {@link #rewrite(com.sun.source.tree.Tree, com.sun.source.tree.Tree) } method,
+     * transitively.
+     * Will return the input tree if the input tree was never passed as the first
+     * parameter of the {@link #rewrite(com.sun.source.tree.Tree, com.sun.source.tree.Tree) }
+     * method.
+     *
+     * <p>Note that the returned tree will be exactly equivalent to a tree passed as
+     * the second parameter to {@link #rewrite(com.sun.source.tree.Tree, com.sun.source.tree.Tree) }.
+     * No attribution or other information will be added (or removed) to (or from) the tree.
+     *
+     * @param in the tree to inspect
+     * @return tree into which the given tree was rewritten using the
+     * {@link #rewrite(com.sun.source.tree.Tree, com.sun.source.tree.Tree) } method,
+     * transitively
+     * @since 0.101
+     */
+    public synchronized @NonNull Tree resolveRewriteTarget(@NonNull Tree in) {
+        Map<Tree, Tree> localChanges = new IdentityHashMap<Tree, Tree>(changes);
+
+        while (localChanges.containsKey(in)) {
+            in = localChanges.remove(in);
+        }
+
+        return in;
+    }
     
     // Package private methods -------------------------------------------------        
     
diff -r b1f8e0d263cc java.source/test/unit/src/org/netbeans/api/java/source/WorkingCopyTest.java
--- a/java.source/test/unit/src/org/netbeans/api/java/source/WorkingCopyTest.java	Mon Apr 02 11:33:38 2012 +0200
+++ b/java.source/test/unit/src/org/netbeans/api/java/source/WorkingCopyTest.java	Mon Apr 02 15:00:52 2012 +0200
@@ -116,4 +116,44 @@
             }
         }, true);
     }
+
+    public void testResolveRewriteTarget() throws Exception {
+        File f = new File(getWorkDir(), "TestClass.java");
+        String code = "package foo;" +
+                      "public class TestClass{" +
+                      "   public void foo() {" +
+                      "   }" +
+                      "}";
+
+        TestUtilities.copyStringToFile(f, code);
+        FileObject fo = FileUtil.toFileObject(f);
+        JavaSource javaSource = JavaSource.forFileObject(fo);
+        javaSource.runModificationTask(new Task<WorkingCopy>() {
+
+            public void run(WorkingCopy copy) throws Exception {
+                copy.toPhase(Phase.RESOLVED);
+
+                TreeMaker maker = copy.getTreeMaker();
+                ClassTree classTree = (ClassTree)copy.getCompilationUnit().getTypeDecls().get(0);
+                TypeElement serializableElement = copy.getElements().getTypeElement("java.io.Serializable");
+                ExpressionTree serializableTree = maker.QualIdent(serializableElement);
+                ClassTree newClassTree = maker.addClassImplementsClause(classTree, serializableTree);
+
+                copy.rewrite(classTree, newClassTree);
+
+                assertSame(newClassTree, copy.resolveRewriteTarget(classTree));
+
+                ClassTree finalClassTree = maker.removeClassImplementsClause(newClassTree, 0);
+
+                copy.rewrite(newClassTree, finalClassTree);
+
+                assertSame(finalClassTree, copy.resolveRewriteTarget(classTree));
+
+                // remove the following to make the test pass
+                copy.toPhase(Phase.RESOLVED);
+            }
+        }).commit();
+
+        assertEquals(code, fo.asText());
+    }
 }