Question

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 exceptionally long Java stacktraces (those will still be available in the full log file).

How would one configure this (using log4j.xml)? Is there a filter available to ignore the stack traces?

Answer 1

Edit after reading some more of the source:

You still need to subclass PatternLayout, but the method you want to override is ignoresThrowable(): it should return false, which will prevent the appender from writing the Throwable (it assumes that the layout has done so already).

No way to specify this in the configuration: PatternLayout has a hardcoded ‘return true’.