Hi,
I'm working on issue https://issues.apache.org/jira/browse/ZEPPELIN-1856 and I
found that we receive a NullPointerException sometimes because a paragraph
result is cleared twice when we run a job. First Paragraph.result is cleared
just before running RemoteInterpreter.interpret(..) and this is ok. But then we
receive an OUTPUT_UPDATE_ALL event from the RemoteInterpreterServer and set
Paragraph.result to null again that may lead to a NullPointerException if
Paragraph.result was already filled by RemoteInterpreter.interpret(..) responce.
To resolve this problem we need to remove
note.clearParagraphOutput(paragraphId) line from the onOutputClear() method in
NotebookServer.java class:
@Override
public void onOutputClear(String noteId, String paragraphId) {
Notebook notebook = notebook();
final Note note = notebook.getNote(noteId);
note.clearParagraphOutput(paragraphId); // this line seems to be wrong
Paragraph paragraph = note.getParagraph(paragraphId);
broadcastParagraph(note, paragraph);
}
This method is called only when RemoteInterpreterServer.interpret(..)
initializes an InterpreterContext and sends an OUTPUT_UPDATE_ALL event.
Is it safe to remove this line or I miss something? It was added by
https://github.com/apache/zeppelin/pull/1658.
Thanks,
Alexander
