While deploying application on Jboss6/Oracle if following warning displays 
  
"WARN [com.arjuna.ats.jta] ARJUNA-16027 Local XARecoveryModule.xaRecovery got XA exception XAException.XAER_RMERR: javax.transaction.xa.XAException" 

to run following commands with sysdba Role 

grant select on sys.dba_pending_transactions to gpmainuser; 
grant select on sys.pending_trans$ to gpmainuser; 
grant select on sys.dba_2pc_pending to gpmainuser; 
grant execute on sys.dbms_system to gpmainuser;

Reference link: https://access.redhat.com/documentation/en-US/JBoss_Enterprise_Application_Platform/6/html/Administration_and_Configuration_Guide/Example_Oracle_XA_Datsource1.html

https://community.jboss.org/thread/220820?tstart=0