How to change a labels location through any type of event (a button in this case)

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

public class GUI extends JFrame{

	private JLabel pic;
	private JButton up,down,right,left;
	private int a = 10;
	private int b = 10;

	
	public GUI(){
		super("AWESOME");
		setLayout(null);
		
		Icon xbox = new ImageIcon(getClass().getResource("xbox.png"));
		pic = new JLabel(xbox);
		pic.setBounds(a, b,50,50);
		pic.setVisible(true);
		
		up = new JButton("");
		up.setBounds(40, 200, 20, 20);
		up.setVisible(true);
		up.addActionListener(
			new ActionListener(){
				public void actionPerformed(ActionEvent event){
					b+=5;
				}
			}
		);
                add(up);
                add(pic);




public class bro {
    public static void main(String args[]) {


        GUI fr = new GUI();
        fr.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        fr.setSize(300, 300);
        fr.setVisible(true);




    }
}