java.lang.NullPointerException
   at com.sun.tools.javadoc.ProgramElementDocImpl.containingPackage(ProgramElementDocImpl.java:118)
   at org.netbeans.api.java.source.ui.ElementJavadoc.getContainingClassOrPackageHeader(ElementJavadoc.java:678)
   at org.netbeans.api.java.source.ui.ElementJavadoc.prepareContent(ElementJavadoc.java:406)
   at org.netbeans.api.java.source.ui.ElementJavadoc.<init>(ElementJavadoc.java:310)
   at org.netbeans.api.java.source.ui.ElementJavadoc.create(ElementJavadoc.java:149)
   at org.netbeans.api.java.source.ui.ElementJavadoc.create(ElementJavadoc.java:135)
   at org.netbeans.modules.java.navigation.CaretListeningTask.computeAndSetJavadoc(CaretListeningTask.java:282)
   at org.netbeans.modules.java.navigation.CaretListeningTask.run(CaretListeningTask.java:223)
   at org.netbeans.modules.java.navigation.CaretListeningTask.run(CaretListeningTask.java:79)
   at org.netbeans.modules.java.source.JavaSourceAccessor$CancelableTaskWrapper.run(JavaSourceAccessor.java:322)
   at org.netbeans.modules.parsing.impl.TaskProcessor$CompilationJob.run(TaskProcessor.java:715)
   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)