Arjuna TM gives an invalid error message in this case, which is misleading: [com.arjuna.ats.internal.jta.transaction.arjunacore.nullres] Resource paramater is null! However, the resource isn't null actually. Check the JTA spec on whether we should throw an exception in this case (and improve/enforce it in Mule, this is not the first time we have to 'patch' products to the spec). Alternatively, consider an improvement to skip the processing (with info message), as the TX is already marked for rollback. While it's trivial in custom component code, need to see the implication for internal flow in Mule.