code: private Object openConnection(ManagedConnection mc, Subject s) throws ResourceException
     {
        if (plugin == null)
           return null;
  
        log.debugf("Open connection (%s, %s)", mc, s);
  
        return mc.getConnection(s, null);
     }
docs: Open a connection
  @param mc The managed connection
  @param s The subject
  @return The connection handle
  @exception ResourceException Thrown in case of an error