java.lang.NullPointerException
   at com.sun.tools.javac.code.Types$ImplementationCache.get(Types.java:2073)
   at com.sun.tools.javac.code.Types.implementation(Types.java:2101)
   at com.sun.tools.javac.code.Symbol$MethodSymbol.implementation(Symbol.java:1320)
   at com.sun.tools.javac.code.Symbol$MethodSymbol.implementation(Symbol.java:1309)
   at com.sun.tools.javac.comp.Check.checkImplementations(Check.java:2063)
   at com.sun.tools.javac.comp.Check.checkImplementations(Check.java:2041)
   at com.sun.tools.javac.comp.Attr.attribClassBody(Attr.java:3295)
   at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:3218)
   at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:3149)
   at com.sun.tools.javac.comp.Attr.attrib(Attr.java:3123)
   at com.sun.tools.javac.main.JavaCompiler.attribute(JavaCompiler.java:1264)
   at com.sun.tools.javac.api.JavacTaskImpl$1.process(JavacTaskImpl.java:461)
   at com.sun.tools.javac.api.JavacTaskImpl$Filter.run(JavacTaskImpl.java:612)
   at com.sun.tools.javac.api.JavacTaskImpl.analyze(JavacTaskImpl.java:464)
   at org.netbeans.modules.java.source.indexing.OnePassCompileWorker.compile(OnePassCompileWorker.java:230)
   at org.netbeans.modules.java.source.indexing.JavaCustomIndexer$1.run(JavaCustomIndexer.java:200)
   at org.netbeans.modules.java.source.indexing.JavaCustomIndexer$1.run(JavaCustomIndexer.java:162)
   at org.netbeans.modules.java.source.usages.ClassIndexManager.prepareWriteLock(ClassIndexManager.java:120)
   at org.netbeans.modules.java.source.indexing.JavaCustomIndexer.index(JavaCustomIndexer.java:162)
   at org.netbeans.modules.parsing.spi.indexing.Indexable$MyAccessor$2.run(Indexable.java:153)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater.runIndexer(RepositoryUpdater.java:257)
   at org.netbeans.modules.parsing.spi.indexing.Indexable$MyAccessor.index(Indexable.java:151)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.doIndex(RepositoryUpdater.java:1846)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.access$1500(RepositoryUpdater.java:1585)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work$2.run(RepositoryUpdater.java:1766)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work$2.run(RepositoryUpdater.java:1764)
   at org.netbeans.modules.parsing.impl.indexing.errors.TaskCache.refreshTransaction(TaskCache.java:460)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.index(RepositoryUpdater.java:1764)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$AbstractRootsWork.scanSource(RepositoryUpdater.java:3520)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$AbstractRootsWork.scanSources(RepositoryUpdater.java:3421)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$RootsWork.getDone(RepositoryUpdater.java:3164)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.doTheWork(RepositoryUpdater.java:2197)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task._run(RepositoryUpdater.java:3930)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task.run(RepositoryUpdater.java:3870)
   at org.netbeans.modules.parsing.impl.TaskProcessor$CompilationJob.run(TaskProcessor.java:649)
   at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
   at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
   at java.util.concurrent.FutureTask.run(FutureTask.java:138)
   at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
   at java.lang.Thread.run(Thread.java:662)