Cannot find elements when XPath expression is null

[devalex88]

@kazurayam

This message does not tell me where the IllegalArgumentException was raised, by which class, by which method in which line. I wanted to see the StackTrace of the IllegalArgumentException. I wondered why the Stack Trace is not printed.

Thank you for the suggestion. We will have an improvement in the next version that allows the original stack trace to be printed out.