code: @Override
      public void commitPreparedTransaction(String xid) throws TransactionException, PersistenceException
      {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.entry(this, tc, "commitPreparedTransaction", xid);
  
          if (_manager != null)
          {
              try
              {
                  PersistentTranId pid = new PersistentTranId(xid);
                  _manager.commit(pid, false);
              } catch (ArrayIndexOutOfBoundsException e)
              {
                  if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled())
                      SibTr.debug(this, tc, "Invalid XID string", xid);
                  throw new XidInvalidException(nls.getString("INVALID_XID_STRING_SIMS1010"));
              } catch (StringIndexOutOfBoundsException e)
              {
                  if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled())
                      SibTr.debug(this, tc, "Invalid XID string", xid);
                  throw new XidInvalidException(nls.getString("INVALID_XID_STRING_SIMS1010"));
              }
          }
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.exit(this, tc, "commitPreparedTransaction");
          return;
      }
docs: Commit the given transaction.
  Given a string representing an xid, create a PersistentTranId
  from it and then request the XidManager to commit it.
  Part of MBean interface for resolving in-doubt transactions.
  
  @param xid a string representing an xid.