We use Log4j (and Commons Logging) to log our error messages. Now we want to set up an additional log appender that outputs fatal errors to syslog, but without the exception
The "nopex" or "nopexception" conversion word in logback-classic (log4j's successor) disables printing stack traces. The "nopex" conversion word is documented along with the rest of conversion words. You need to scroll down a little.
If you need further information on this topic, please contact the logback-user mailing list.