Why did Servlet.service() for servlet jsp throw this exception?

Question

I get the following error, what could be the problem?

My context descriptor:

Answer 1

The problem is in your JSP, most likely you are calling a method on an object that is null at runtime.

It is happening in the _jspInit() call, which is a little more unusual... the problem code is probably a method declaration like <%! %>

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Update: I've only reproduced this by overriding the _jspInit() method. Is that what you're doing? If so, it's not recommended - that's why it starts with an _.