code: private boolean closeConnection(Object c)
     {
        if (plugin == null)
           return false;
  
        log.debugf("Closing connection for recovery check (%s)", c);
  
        boolean forceClose = false;
  
        if (c != null)
        {
           try
           {
              forceClose = !plugin.isValid(c);
           }
           catch (ResourceException re)
           {
              log.debugf("Error during recovery plugin isValid()", re);
              forceClose = true;
           }
  
           try
           {
              plugin.close(c);
           }
           catch (ResourceException re)
           {
              log.debugf("Error during recovery plugin close()", re);
              forceClose = true;
           }
        }
  
        log.debugf("Force close=%s", forceClose);
  
        return forceClose;
     }
docs: Close a connection
  @param c The connection
  @return Should the managed connection be forced closed