I2JAV11 — Usage of ExceptionDetailMessage service context

The interop RTF resolved issue 3405 by adding a new service context called
ExceptionDetailMessage. The usage of this service context was
left to language mappings to define. We need to define this usage for Java.

Writing the service context:

There are a few possibilities that come to mind:
1) The result of calling getMessage() on the exception.
2) The result of calling toString() on the exception.
3) The result of calling printStackTrace(PrintWriter) on the exception.

I'm inclined to think that option 3 is best, since the callee's stack trace
is often very valuable debugging information.

Reading the service context:

The wstring from the service context should become the Java error message
in the unmarshalled exception object.

issue has been resolved, see ptc/01-10-20