webservice error reason

In the case of only WSDL, the server is called after generating the client through WSDL2.java.

An error message similar to the following appears

Caused by: com.ctc.wstx.exc.WstxUnexpectedCharException: Unexpected character 'X' (code XX) in prolog; expected 'X'
Specifically
Caused by: com.ctc.wstx.exc.WstxUnexpectedCharException: Unexpected character 'E' (code 69) in prolog; expected '<'

This kind of exception may not be a problem with the client's program, but a problem with the message returned by the server. You need to find the server side to check the reason together.

My server-side provider gives me the implementation of a complex object. If I pass empty parameters, it will return to normal, and if I pass specific parameters, it will report an error, indicating that it is not a client-side program problem.