java.lang.AssertionError: duplicate context value
   at com.sun.tools.javac.util.Context.put(Context.java:129)
   at com.sun.tools.javadoc.Messager.preRegister(Messager.java:77)
   at org.netbeans.modules.java.source.parsing.JavacParser.createJavacTask(JavacParser.java:802)
   at org.netbeans.modules.java.source.parsing.JavacParser.createJavacTask(JavacParser.java:715)
   at org.netbeans.modules.java.source.parsing.CompilationInfoImpl.getJavacTask(CompilationInfoImpl.java:398)
   at org.netbeans.modules.java.source.parsing.JavacParser.getResult(JavacParser.java:493)
   at org.netbeans.modules.java.source.parsing.JavacParser.getResult(JavacParser.java:169)
   at org.netbeans.modules.parsing.impl.TaskProcessor.callGetResult(TaskProcessor.java:606)
   at org.netbeans.modules.parsing.impl.SourceCache.getResult(SourceCache.java:247)
   at org.netbeans.modules.parsing.impl.TaskProcessor$CompilationJob.run(TaskProcessor.java:718)
   at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
   at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
   at java.util.concurrent.FutureTask.run(FutureTask.java:166)
   at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
   at java.lang.Thread.run(Thread.java:722)