Window Builder i Eclipse

import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.GridLayout;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class LMFun extends JFrame {
    private static final long serialVersionUID = 1L;
    public LMFun() {
        setTitle("LayoutManager fun");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        getContentPane().setLayout(new BorderLayout());
        getContentPane().add(new JLabel("West"), BorderLayout.WEST);
        getContentPane().add(new JLabel("East"), BorderLayout.EAST);
        JPanel north = new JPanel();
        north.setLayout(new FlowLayout(FlowLayout.LEFT));
        north.add(new JLabel("North 1"));
        north.add(new JLabel("North 2"));
        north.add(new JLabel("North 3"));
        getContentPane().add(north, BorderLayout.NORTH);
        JPanel south = new JPanel();
        south.setLayout(new FlowLayout(FlowLayout.LEFT));
        south.add(new JLabel("South 1"));
        south.add(new JLabel("South 2"));
        south.add(new JLabel("South 3"));
        getContentPane().add(south, BorderLayout.SOUTH);
        JPanel center = new JPanel();
        center.setLayout(new GridLayout(2, 3));
        center.add(new JLabel("Center (1,1)"));
        center.add(new JLabel("Center (1,2)"));
        center.add(new JLabel("Center (1,3)"));
        center.add(new JLabel("Center (2,1)"));
        center.add(new JLabel("Center (2,2)"));
        center.add(new JLabel("Center (2,3)"));
        getContentPane().add(center, BorderLayout.CENTER);
        pack();
    }
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                JFrame f = new LMFun();
                f.setVisible(true);
            }
        });
    }
}