Github user Leemoonsoo commented on the pull request:
https://github.com/apache/incubator-zeppelin/pull/213#issuecomment-131468829
Thanks @prabhjyotsingh for fix.
I've tested this branch and i can see reconnection is working.
Once reconnected, however, any command is not working but raising
exceptions such as
```
6:09:06,063 ERROR org.apache.zeppelin.socket.NotebookServer:141 - Can't
handle message
java.lang.NullPointerException
at
org.apache.zeppelin.socket.NotebookServer.updateParagraph(NotebookServer.java:373)
at
org.apache.zeppelin.socket.NotebookServer.onMessage(NotebookServer.java:107)
at
org.apache.zeppelin.socket.NotebookSocket.onMessage(NotebookSocket.java:56)
at
org.eclipse.jetty.websocket.WebSocketConnectionRFC6455$WSFrameHandler.onFrame(WebSocketConnectionRFC6455.java:835)
at
org.eclipse.jetty.websocket.WebSocketParserRFC6455.parseNext(WebSocketParserRFC6455.java:349)
at
org.eclipse.jetty.websocket.WebSocketConnectionRFC6455.handle(WebSocketConnectionRFC6455.java:225)
at
org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:667)
at
org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:52)
at
org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)
at
org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)
at java.lang.Thread.run(Thread.java:745)
```
Therefore, user can not be benefit by re-connected websocket.
It is because of NotebookServer searches Note by websocket connection in
[NoteSocketMap](https://github.com/apache/incubator-zeppelin/blob/master/zeppelin-server/src/main/java/org/apache/zeppelin/socket/NotebookServer.java#L59).
To creates information into NoteSocketMap, client need to send
[GET_NOTE](https://github.com/apache/incubator-zeppelin/blob/master/zeppelin-server/src/main/java/org/apache/zeppelin/socket/NotebookServer.java#L113)
message, once it is reconnected.
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