java.lang.NullPointerException
        at com.sun.tools.javac.api.JavacTrees.getElement(JavacTrees.java:182)
        at org.netbeans.modules.web.wicket.tree.AssignmentTracer.visitReturn(AssignmentTracer.java:63)
        at org.netbeans.modules.web.wicket.tree.AssignmentTracer.visitReturn(AssignmentTracer.java:31)
        at com.sun.tools.javac.tree.JCTree$JCReturn.accept(JCTree.java:1224)
        at com.sun.source.util.TreeScanner.scan(TreeScanner.java:76)
        at com.sun.source.util.TreeScanner.scanAndReduce(TreeScanner.java:80)
        at com.sun.source.util.TreeScanner.scan(TreeScanner.java:90)
        at com.sun.source.util.TreeScanner.visitBlock(TreeScanner.java:159)
        at com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:777)
        at com.sun.source.util.TreeScanner.scan(TreeScanner.java:76)
        at com.sun.source.util.TreeScanner.scanAndReduce(TreeScanner.java:80)
        at com.sun.source.util.TreeScanner.visitMethod(TreeScanner.java:142)
        at com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:677)
        at org.netbeans.modules.web.wicket.tree.AssignmentTracer.traceMethodInvocation(AssignmentTracer.java:90)
        at org.netbeans.modules.web.wicket.tree.AssignmentTracer.visitVariable(AssignmentTracer.java:107)
        at org.netbeans.modules.web.wicket.tree.AssignmentTracer.visitVariable(AssignmentTracer.java:31)
        at com.sun.tools.javac.tree.JCTree$JCVariableDecl.accept(JCTree.java:723)
        at org.netbeans.modules.web.wicket.tree.AddToMarkupContainerFinder.visitMethodInvocation(AddToMarkupContainerFinder.java:163)
        at org.netbeans.modules.web.wicket.tree.AddToMarkupContainerFinder.visitMethodInvocation(AddToMarkupContainerFinder.java:29)
        at com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1311)
        at com.sun.source.util.TreeScanner.scan(TreeScanner.java:76)
        at com.sun.source.util.TreeScanner.visitExpressionStatement(TreeScanner.java:239)
        at com.sun.tools.javac.tree.JCTree$JCExpressionStatement.accept(JCTree.java:1151)
        at com.sun.source.util.TreeScanner.scan(TreeScanner.java:76)
        at com.sun.source.util.TreeScanner.scanAndReduce(TreeScanner.java:80)
        at com.sun.source.util.TreeScanner.scan(TreeScanner.java:90)
        at com.sun.source.util.TreeScanner.visitBlock(TreeScanner.java:159)
        at com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:777)
        at com.sun.source.util.TreeScanner.scan(TreeScanner.java:76)
        at com.sun.source.util.TreeScanner.scanAndReduce(TreeScanner.java:80)
        at com.sun.source.util.TreeScanner.visitMethod(TreeScanner.java:142)
        at com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:677)
        at com.sun.source.util.TreeScanner.scan(TreeScanner.java:76)
        at com.sun.source.util.TreeScanner.scan(TreeScanner.java:90)
        at com.sun.source.util.TreeScanner.scanAndReduce(TreeScanner.java:98)
        at com.sun.source.util.TreeScanner.visitClass(TreeScanner.java:132)
        at com.sun.tools.javac.tree.JCTree$JCClassDecl.accept(JCTree.java:604)
        at org.netbeans.modules.web.wicket.tree.JavaTreeBuilder$T.run(JavaTreeBuilder.java:165)
        at org.netbeans.modules.web.wicket.tree.JavaTreeBuilder$T.run(JavaTreeBuilder.java:86)
        at org.netbeans.api.java.source.JavaSource$MultiTask.run(JavaSource.java:450)
        at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:129)
        at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:113)
        at org.netbeans.modules.parsing.impl.TaskProcessor.runUserTask(TaskProcessor.java:189)
        at org.netbeans.modules.parsing.api.ParserManager.parse(ParserManager.java:99)
        at org.netbeans.api.java.source.JavaSource.runUserActionTaskImpl(JavaSource.java:405)
        at org.netbeans.api.java.source.JavaSource.runUserActionTask(JavaSource.java:376)
        at org.netbeans.modules.web.wicket.tree.JavaTreeBuilder.analyze(JavaTreeBuilder.java:71)
        at org.netbeans.modules.web.wicket.verification.WicketProblemAnnotationProvider.annotate(WicketProblemAnnotationProvider.java:186)
        at org.netbeans.modules.web.wicket.verification.WicketProblemAnnotationProvider.annotate(WicketProblemAnnotationProvider.java:175)
        at org.netbeans.modules.web.wicket.verification.WicketProblemAnnotationProvider.annotate(WicketProblemAnnotationProvider.java:118)
        at org.netbeans.modules.web.wicket.verification.WicketProblemAnnotationProvider.access$700(WicketProblemAnnotationProvider.java:59)
        at org.netbeans.modules.web.wicket.verification.WicketProblemAnnotationProvider$ScanningDocumentListener.run(WicketProblemAnnotationProvider.java:554)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:577)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1030)