java.lang.IllegalArgumentException: Unsupported type: <nulltype>, kind: NULL
   at org.netbeans.modules.java.source.usages.ClassFileUtil.encodeType(ClassFileUtil.java:319)
   at org.netbeans.modules.java.source.usages.ClassFileUtil.createExecutableDescriptor(ClassFileUtil.java:198)
   at org.netbeans.api.java.source.ElementHandle.createImpl(ElementHandle.java:458)
   at org.netbeans.api.java.source.ElementHandle.create(ElementHandle.java:397)
   at org.netbeans.api.java.source.ui.ElementJavadoc.createLink(ElementJavadoc.java:1534)
   at org.netbeans.api.java.source.ui.ElementJavadoc.getAnnotations(ElementJavadoc.java:1056)
   at org.netbeans.api.java.source.ui.ElementJavadoc.getMethodHeader(ElementJavadoc.java:896)
   at org.netbeans.api.java.source.ui.ElementJavadoc.prepareContent(ElementJavadoc.java:507)
   at org.netbeans.api.java.source.ui.ElementJavadoc.<init>(ElementJavadoc.java:385)
   at org.netbeans.api.java.source.ui.ElementJavadoc.create(ElementJavadoc.java:166)
   at org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery$3.create(JavaCompletionProvider.java:276)
   at org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery$3.create(JavaCompletionProvider.java:272)
   at org.netbeans.modules.java.completion.JavaDocumentationTask.resolve(JavaDocumentationTask.java:112)
   at org.netbeans.modules.java.completion.BaseTask.run(BaseTask.java:92)
   at org.netbeans.modules.java.completion.JavaDocumentationTask.run(JavaDocumentationTask.java:62)
   at org.netbeans.modules.parsing.impl.TaskProcessor.callUserTask(TaskProcessor.java:609)
   at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:153)
   at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:137)
   at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:204)
   at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:201)
   at org.netbeans.modules.masterfs.filebasedfs.utils.FileChangedManager.priorityIO(FileChangedManager.java:176)
   at org.netbeans.modules.masterfs.providers.ProvidedExtensions.priorityIO(ProvidedExtensions.java:360)
   at org.netbeans.modules.parsing.nb.DataObjectEnvFactory.runPriorityIO(DataObjectEnvFactory.java:141)
   at org.netbeans.modules.parsing.impl.Utilities.runPriorityIO(Utilities.java:88)
Caused: org.netbeans.modules.parsing.spi.ParseException
   at org.netbeans.modules.parsing.impl.TaskProcessor.runUserTask(TaskProcessor.java:209)
   at org.netbeans.modules.parsing.api.ParserManager.parse(ParserManager.java:104)
   at org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery.query(JavaCompletionProvider.java:284)
   at org.netbeans.spi.editor.completion.support.AsyncCompletionTask.run(AsyncCompletionTask.java:223)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1425)
   at org.netbeans.modules.openide.util.GlobalLookup.execute(GlobalLookup.java:68)
   at org.openide.util.lookup.Lookups.executeWith(Lookups.java:303)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2038)