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

public class SomeClass {

    public void init() {
        JFrame frame = new JFrame();
        JLayeredPane jlp = new JLayeredPane();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);

        frame.setSize(600, 600);
        frame.add(jlp);

        for (int i = 4; i > 0; i--) {
            JPanel panel = new JPanel();
            panel.setBounds(0, 100 * i, 400, 100);
            panel.add(new JButton(String.valueOf(i)));
            if (i % 2 == 0) {
                panel.setBackground(Color.red);

            } else {
                panel.setBackground(Color.black);
            }
            jlp.add(panel);
        }
    }

    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                SomeClass classObj = new SomeClass();
                classObj.init();
            }
        });
    }
}