java.lang.NullPointerException
   at com.sun.tools.javac.comp.MemberEnter$Synthesizer.visit(MemberEnter.java:1583)
   at com.sun.tools.javac.comp.MemberEnter$7.getModelType(MemberEnter.java:1565)
   at com.sun.tools.javac.code.Symbol$ClassSymbol.getSuperclass(Symbol.java:1054)
   at com.sun.tools.javac.code.Types$20.visitClassType(Types.java:2297)
   at com.sun.tools.javac.code.Types$20.visitClassType(Types.java:2286)
   at com.sun.tools.javac.code.Type$ClassType.accept(Type.java:752)
   at com.sun.tools.javac.code.Types$UnaryVisitor.visit(Types.java:4473)
   at com.sun.tools.javac.code.Types.supertype(Types.java:2283)
   at com.sun.tools.javac.code.Types$15.visitClassType(Types.java:1945)
   at com.sun.tools.javac.code.Types$15.visitClassType(Types.java:1934)
   at com.sun.tools.javac.code.Type$ClassType.accept(Type.java:752)
   at com.sun.tools.javac.code.Types$DefaultTypeVisitor.visit(Types.java:4392)
   at com.sun.tools.javac.code.Types.asSuper(Types.java:1931)
   at com.sun.tools.javac.code.Types$6.visitClassType(Types.java:908)
   at com.sun.tools.javac.code.Types$6.visitClassType(Types.java:826)
   at com.sun.tools.javac.code.Type$ClassType.accept(Type.java:752)
   at com.sun.tools.javac.code.Types$DefaultTypeVisitor.visit(Types.java:4392)
   at com.sun.tools.javac.code.Types.isSubtype(Types.java:822)
   at com.sun.tools.javac.code.Types.isSubtype(Types.java:792)
   at com.sun.tools.javac.code.Types.isSubtypeUncheckedInternal(Types.java:745)
   at com.sun.tools.javac.code.Types.isSubtypeUnchecked(Types.java:729)
   at com.sun.tools.javac.code.Types.isConvertible(Types.java:304)
   at com.sun.tools.javac.code.Types.isAssignable(Types.java:2143)
   at com.sun.tools.javac.code.Types.isAssignable(Types.java:2106)
   at com.sun.tools.javac.model.JavacTypes.isAssignable(JavacTypes.java:107)
   at org.netbeans.modules.java.source.matching.CopyFinder.scan(CopyFinder.java:368)
   at org.netbeans.modules.java.source.matching.CopyFinder.scan(CopyFinder.java:578)
   at org.netbeans.modules.java.source.matching.CopyFinder.checkListsWithMultistatementTrees(CopyFinder.java:698)
   at org.netbeans.modules.java.source.matching.CopyFinder.checkListsWithMultistatementTrees(CopyFinder.java:730)
   at org.netbeans.modules.java.source.matching.CopyFinder.checkLists(CopyFinder.java:606)
   at org.netbeans.modules.java.source.matching.CopyFinder.visitMethodInvocation(CopyFinder.java:597)
   at org.netbeans.modules.java.source.matching.CopyFinder.visitMethodInvocation(CopyFinder.java:117)
   at com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1477)
   at com.sun.source.util.TreeScanner.scan(TreeScanner.java:77)
   at org.netbeans.modules.java.source.matching.CopyFinder.doSuperScan(CopyFinder.java:565)
   at org.netbeans.modules.java.source.matching.CopyFinder.superScan(CopyFinder.java:557)
   at org.netbeans.modules.java.source.matching.CopyFinder.scan(CopyFinder.java:452)
   at org.netbeans.modules.java.source.matching.CopyFinder.scan(CopyFinder.java:315)
   at org.netbeans.modules.java.source.matching.CopyFinder.internalComputeDuplicates(CopyFinder.java:182)
   at org.netbeans.api.java.source.matching.Matcher.match(Matcher.java:189)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker.doComputeHints(HintsInvoker.java:551)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker.computeHintsImpl(HintsInvoker.java:294)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker.computeHints(HintsInvoker.java:239)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker.computeHints(HintsInvoker.java:209)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker.computeHints(HintsInvoker.java:182)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker.computeHints(HintsInvoker.java:149)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsTask.run(HintsTask.java:114)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsTask.run(HintsTask.java:83)
   at org.netbeans.modules.java.source.JavaSourceAccessor$CancelableTaskWrapper.run(JavaSourceAccessor.java:298)
   at org.netbeans.modules.parsing.impl.TaskProcessor.callParserResultTask(TaskProcessor.java:568)
   at org.netbeans.modules.parsing.impl.TaskProcessor$CompilationJob.run(TaskProcessor.java:744)
   at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
   at java.util.concurrent.FutureTask.run(FutureTask.java:262)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1432)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2042)