Swing GUI Java

package com.samkough.main;

/*
LINKS:
http://www.wikihow.com/Create-a-Swing-GUI-in-Java
https://stackoverflow.com/questions/144892/how-to-centre-a-window-in-java
*/

import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.*;

@SuppressWarnings("serial")
public class Swing extends JFrame implements ActionListener
{
	JPanel mypanel;
	JButton mybutton;
	JLabel mylabel;

	public static void main(String args[])
	{
		Swing first = new Swing();
		first.setTitle("First Try");
		first.setSize(300,200);
		first.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		first.setVisible(true);
		first.setLocationRelativeTo(null);
	}

	public Swing()
	{
		mypanel = new JPanel();

		mybutton = new JButton("OK");
		mybutton.addActionListener(this);

		mylabel = new JLabel();

		mypanel.add(mybutton);
		mypanel.add(mylabel);
		this.add(mypanel);
	}

	public void actionPerformed(ActionEvent event)
	{
		if(event.getSource() == mybutton)
		{
			mylabel.setText("My button clicked.");
		}
	}

}