throw new IllegalArgumentException("Default close operation must be one of DO_NOTHING_ON_CLOSE, HIDE_ON_CLOSE, or DISPOSE_ON_CLOSE");
close_action = DO_NOTHING_ON_CLOSE;
  public void setDefaultCloseOperation(int operation)  {    if (operation == DO_NOTHING_ON_CLOSE ||    	operation == HIDE_ON_CLOSE ||	operation == DISPOSE_ON_CLOSE)      close_action = operation;    else      throw new IllegalArgumentException("Default close operation must be one of DO_NOTHING_ON_CLOSE, HIDE_ON_CLOSE, or DISPOSE_ON_CLOSE");  }