When calling

log.error("failure: %s", new NullPointerException("booom"));

, the stack trace of the exception is not shown immediately following the error string:

704 [ERROR] jgroups: failure: %s
java.lang.NullPointerException: booom
        at org.jgroups.tests.bla4.main(bla4.java:14) [classes/:?]

Invoking toString() on the exception works, but in some cases, we want to be able to see the stack trace.
Investigate how to show the stack trace on all (currently) 3 loggers (JDK, log4j and log4j2).