java.lang.NullPointerException
   at com.sun.tools.javac.processing.JavacProcessingEnvironment$Round.unrecoverableError(JavacProcessingEnvironment.java:1153)
   at com.sun.tools.javac.processing.JavacProcessingEnvironment.doProcessing(JavacProcessingEnvironment.java:1323)
   at com.sun.tools.javac.main.JavaCompiler.processAnnotations(JavaCompiler.java:1326)
   at com.sun.tools.javac.main.JavaCompiler.processAnnotations(JavaCompiler.java:1214)
   at com.sun.tools.javac.main.JavaCompiler.lambda$readSourceFile$191(JavaCompiler.java:907)
   at com.sun.tools.javac.code.ClassFinder.complete(ClassFinder.java:315)
   at com.sun.tools.javac.code.Symbol.complete(Symbol.java:636)
   at com.sun.tools.javac.code.Symbol$ClassSymbol.complete(Symbol.java:1325)
   at com.sun.tools.javac.code.Symbol$ClassSymbol.flags(Symbol.java:1250)
   at com.sun.tools.javac.code.Symbol$TypeSymbol.getEnclosedElements(Symbol.java:803)
   at org.netbeans.modules.java.editor.base.imports.UnusedImports$DetectorVisitor.visitImport(UnusedImports.java:273)
   at org.netbeans.modules.java.editor.base.imports.UnusedImports$DetectorVisitor.visitImport(UnusedImports.java:130)
   at com.sun.tools.javac.tree.JCTree$JCImport.accept(JCTree.java:662)
   at com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:82)
   at org.netbeans.api.java.source.support.CancellableTreePathScanner.scan(CancellableTreePathScanner.java:94)
   at com.sun.source.util.TreeScanner.scanAndReduce(TreeScanner.java:90)
   at com.sun.source.util.TreeScanner.scan(TreeScanner.java:105)
   at org.netbeans.api.java.source.support.CancellableTreePathScanner.scan(CancellableTreePathScanner.java:103)
   at org.netbeans.modules.java.editor.base.imports.UnusedImports$DetectorVisitor.visitCompilationUnit(UnusedImports.java:189)
   at org.netbeans.modules.java.editor.base.imports.UnusedImports$DetectorVisitor.visitCompilationUnit(UnusedImports.java:130)
   at com.sun.tools.javac.tree.JCTree$JCCompilationUnit.accept(JCTree.java:593)
   at com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:82)
   at org.netbeans.api.java.source.support.CancellableTreePathScanner.scan(CancellableTreePathScanner.java:94)
   at org.netbeans.modules.java.editor.base.imports.UnusedImports.process(UnusedImports.java:108)
   at org.netbeans.modules.java.editor.base.imports.UnusedImports.computeUnusedImports(UnusedImports.java:92)
   at org.netbeans.modules.java.hints.Imports.unusedImport(Imports.java:96)
   at sun.reflect.NativeMethodAccessorImpl.invoke0(NativeMethodAccessorImpl.java:0)
   at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
   at java.lang.reflect.Method.invoke(Method.java:498)
   at org.netbeans.modules.java.hints.providers.code.CodeHintProviderImpl$WorkerImpl.createErrors(CodeHintProviderImpl.java:340)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker.runHint(HintsInvoker.java:821)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker.access$400(HintsInvoker.java:113)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker$ScannerImpl.runAndAdd(HintsInvoker.java:680)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker$ScannerImpl.scan(HintsInvoker.java:718)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker.computeHintsImpl(HintsInvoker.java:268)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker.computeHints(HintsInvoker.java:251)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker.computeHints(HintsInvoker.java:216)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker.computeHints(HintsInvoker.java:189)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker.computeHints(HintsInvoker.java:151)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsTask.run(HintsTask.java:137)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsTask.run(HintsTask.java:88)
   at org.netbeans.modules.java.source.JavaSourceAccessor$CancelableTaskWrapper.run(JavaSourceAccessor.java:298)
   at org.netbeans.modules.parsing.impl.TaskProcessor.callParserResultTask(TaskProcessor.java:584)
   at org.netbeans.modules.parsing.impl.TaskProcessor$RequestPerformer.run(TaskProcessor.java:809)
   at org.openide.util.lookup.Lookups.executeWith(Lookups.java:304)
   at org.netbeans.modules.parsing.impl.TaskProcessor$RequestPerformer.execute(TaskProcessor.java:725)
   at org.netbeans.modules.parsing.impl.TaskProcessor$CompilationJob.run(TaskProcessor.java:686)
   at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
   at java.util.concurrent.FutureTask.run(FutureTask.java:266)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1443)
   at org.netbeans.modules.openide.util.GlobalLookup.execute(GlobalLookup.java:68)
   at org.openide.util.lookup.Lookups.executeWith(Lookups.java:303)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2058)