It’s hard to read your last post, but when I tried to throw an exception from JavaDelegate, it’s handled in PvmAtomicOperationActivityExecute by rethrowing it wrapped in PvmException. So it creates another stacktrace which is then passed to slf4j and then to your loggin implementation. And it’s up to the implementation how it will get handled. If the whole stacktrace is somewhere set as an exception message, then there’s a problem, but I doubt that’s the case.
I’m using log4j2 implementation and I can add %ex{short} to my PatternLayout and then I will only get the first line of the stacktrace and there are other options: https://logging.apache.org/log4j/log4j-2.0/manual/layouts.html