code: public void commit(Xid xid, boolean onePhase) throws XAException
     {
        if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.entry(this, tc, "commit",
                                             new Object[] {xid, ""+onePhase});
        
        internalCommit(xid, onePhase);
        
        if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.exit(this, tc, "commit");
     }
docs: Called when the transaction manager wishes to commit the
  transaction represented by this Xid.
  <p>
  Across the wire we will flow:
  <p>
  BIT32    TransactionId
  The XID Structure
  BYTE     OnePhase (0x00 = false, 0x01 = true)
  
  @param xid
  @param onePhase
  
  @throws XAException if an exception is thrown at the ME. In the
  event of a comms failure, an XAException with XAER_RMFAIL will
  be thrown.