public synchronized ConnectionDecorator removeRecoveryCallback(ConnectionDecorator cb){
  if (cb == null)   throw new NullPointerException("null callback");
  return (recovery_callbacks_.remove(cb) ? cb : null);
}

public synchronized ConnectionDecorator removeRecoveryCallback ( ConnectionDecorator cb ) { if ( cb == null ) throw new NullPointerException ( "null callback" ) ; return ( recovery_callbacks_ . remove ( cb ) ? cb : null ) ; }
remove a previously registered callback .
