Java problem mit dem ActionListener

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

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JTextField;

public class SubWin extends JFrame {
	
	public static void main(String[] args) {
		new SubWin();
	}


	public SubWin() {
		class DerHandler implements ActionListener{
			


			public void actionPerformed(ActionEvent event) {
				if(event.getSource()==button1)
					JOptionPane.showMessageDialog(null, "test");
				
						}	
					}
		
		setVisible(true);
		setLocationRelativeTo(null);
		setSize(200,200);
		setTitle("Label");
		getContentPane().setLayout(null);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
		
		//Menu
		//Labels
		JLabel label = new JLabel();
		label.setLocation(10, 10);
		label.setSize(100, 10);
		label.setText("Test");
		add(label);
		//Button
		JButton button1 = new JButton("");
		button1.setBounds(10, 30, 20, 20);
		add(button1);		
		//Input
		JTextField input = new JTextField(10);
		add(input);
		
		DerHandler handler = new DerHandler();
		button1.addActionListener(handler);
			
	}
}

button1.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent args)
{
if(args.getSource() == button1)
{
//do 
}
}
});

@Override
public void actionPerformed(ActionEvent e) {
...
...
}