void setDefaultCloseOperation(int operation) {  close_action = operation;   }
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"); }
    void setDefaultCloseOperation(int operation)    {  close_action = operation;   }