[ZEPPELIN-4712]remove paragraph failed due to Interpreter connection refused

[xiejiajun]

What is this PR for?

• an interpreter process refused to connect due to it abnormal stop , which eventually caused the remove paragraph operation to fail to complete when i try remove a paragraph.

What type of PR is it?

• Bug Fix

What is the Jira issue?

• https://issues.apache.org/jira/browse/ZEPPELIN-4712

Questions:

Does the licenses files need update? NO
Is there breaking changes for older versions? NO
Does this needs documentation? NO

[zjffdu]

I think we should add throw Exception for method removeResourcesBelongsToParagraph and let the caller decide how to handle the exception. What do you think ?

[xiejiajun]

I think we should add throw Exception for method removeResourcesBelongsToParagraph and let the caller decide how to handle the exception. What do you think ?

@zjffdu , i have considered this. If we do this, removeNote, removeFolder, and removeParagraph will need to handle this exception separately.

[xiejiajun]

I think we should add throw Exception for method removeResourcesBelongsToParagraph and let the caller decide how to handle the exception. What do you think ?

another purpose of caught this exception in the removeResourcesBelongsToParagraph method is in order to make other running interpreters can release resources that related to the paragraph that needs to be removed. @zjffdu

[zjffdu]

Sorry for late response, @xiejiajun Your explanation make sense to me. I think we need to improve the exception handling where we don't have very well convention. Currently your PR LGTM for fixing this issue