import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;

class BigB extends JButton {
    BigB(String label) {
        super(label);
    }

    public Dimension getPreferredSize() {
        Dimension oyaD = super.getPreferredSize();
        return new Dimension(oyaD.width * 2, oyaD.height * 2);
    }
}

public class FirstGUI implements ActionListener {
    static JFrame parent;

    public static void main(String[] args) {

        JFrame jf = new JFrame("FirstGUI");
        jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        parent = jf;

        JButton jb = new BigB("BigSize asfdasdfasdf sdf");// JButton("Button");
        jf.getContentPane().add(jb);
        jf.getContentPane().add(new JButton("2nd Button"), BorderLayout.SOUTH);
        jb.addActionListener(new FirstGUI());
        jf.setSize(300, 300);
        jf.setVisible(true);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        System.out.println(e.getActionCommand());
        parent.pack();
    }
}