JAVA GUI : JButton & Action

// paket yang diperlukan
import javax.swing.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

class ContohTombol extends JFrame{
    // attribut
    //membuat tombol
    JButton tombol1 = new JButton("Tombol 1");
    JButton tombol2 = new JButton("Tombol 2");
    JLabel text_label = new JLabel("Pilih & Klik 1 tombol");

    //konstruktor
    public ContohTombol(){
        //frame seting---------------------------------------------------------------------
        //memanggil konstruktor kelas induk (JFrame)
        super("Contoh Tombol");
        //seting besar frame 400 x 400 px
        this.setSize(200,200);
        //seting agar bisa ditutup
        this.setDefaultCloseOperation(EXIT_ON_CLOSE);
        //seting kemunculan frame di tengah window
        this.setLocationRelativeTo(null);
        //seting layout frame
        this.getContentPane().setLayout(null);
        //frame seting---------------------------------------------------------------------
        //menambahkan komponen ke frame dan seting letak
        this.add(tombol1);
        this.add(tombol2);
        this.add(text_label);
        // setbounds(x,y,lebar,tinggi)
        tombol1.setBounds(10,10,150,25);
        tombol2.setBounds(10,40,150,25);
        text_label.setBounds(10,70,150,25);
        //seting aksi tombol
        tombol1.addActionListener(new ActionListener( ) {
            public void actionPerformed(ActionEvent e){
                // kode disini; saat di klik string text_label akan berubah
                text_label.setText("Tombol 1 di klik");
            }
        });
        tombol2.addActionListener(new ActionListener( ) {
            public void actionPerformed(ActionEvent e){
                // kode disini; saat di klik string text_label akan berubah
                text_label.setText("Tombol 2 di klik");
            }
        });
        // menampilkan frame
        show();

    }

    public static void main(String[] args){
        new ContohTombol();
    }
}