import java.awt.GridBagLayout;
import javax.swing.JPanel;
import javax.swing.JButton;
import java.awt.GridBagConstraints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class HelloPanel extends JPanel {

    private static final long serialVersionUID = 1L;
    private JButton HelloButton = null;

    /**
     * This is the default constructor
     */
    public HelloPanel() {
        super();
        initialize();
    }

    /**
     * This method initializes this
     *
     * @return void
     */
    private void initialize() {
        GridBagConstraints gridBagConstraints = new GridBagConstraints();
        gridBagConstraints.gridx = 0;
        gridBagConstraints.gridheight = 2;
        gridBagConstraints.gridy = 0;
        this.setSize(300, 200);
        this.setLayout(new GridBagLayout());
        this.add(getHelloButton(), gridBagConstraints);
    }

    /**
     * This method initializes HelloButton
     *
     * @return javax.swing.JButton
     */
    private JButton getHelloButton() {
        if (HelloButton == null) {
            HelloButton = new JButton("Hello");
            HelloAction ha =new HelloAction();
            HelloButton.addActionListener(ha);
        }
        return HelloButton;
    }

    class HelloAction implements ActionListener{
        @Override
        public void actionPerformed(ActionEvent e) {
            System.out.println("hello");
        }

    }

}