The arjuna code uses pattern e.printStackTrace() on several places in the code. This would be better to be changed for a logger would be used.

For ArjunaJTA I counted 28 (excluding tests) places where the logger is not used and I suppose it should be.

Secondary. It would be nice in case of the XAException the error code would be printed together with the exception stacktrace. I have one example where I would appreciated it for example.
It's ArjunaJTA/jta/classes/com/arjuna/ats/internal/jta/recovery/arjunacore/XARecoveryModule.java
method handleOrphan where after the xares.rollback(xid) is called the exception is printed to stdout + log does not contain the error code.

This issue was moved from https://bugzilla.redhat.com/show_bug.cgi?id=1007384.