The message says the root cause is a NullPointerException (NPE).
Some people say the NPE is the commonest and most annoying mistake in Java. This is obviously discussed often on JavaRanch. The first thing to do is to get more details (as David has told you). Find where that occurs and put lots of informative code in the catch block, including exc.printStackTrace(); (where "exc" is what you wrote in the () after catch). Follow the stack trace back to where you might have something which is null.
Do a search and you get useful old posts like
this,
this,
this, and there will be lots more. Read those threads; what you are interested in is not what happened, but how we suggested they sort out their NPEs. You need to do the same.