Java SpringLayout set x/y constraints

import javax.swing.SpringLayout; 
import java.awt.Container; 
import javax.swing.JFrame; 
import javax.swing.JButton; 
import javax.swing.Spring; 

public class Main { 
    public static void main(String[] args) { 
        JFrame frame = new JFrame("SpringLayout2"); 
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
        Container contentPane = frame.getContentPane(); 

        // Set the content pane's layout to a SpringLayout 
        SpringLayout springLayout = new SpringLayout(); 
        contentPane.setLayout(springLayout); 

        // Add two JButtons to the content pane 
        JButton b1 = new JButton("Button 1"); 
        JButton b2 = new JButton("Little Bigger Button 2"); 

        // Create Constraints objects for b1 and b2 
        SpringLayout.Constraints b1c = new SpringLayout.Constraints(); 
        SpringLayout.Constraints b2c = new SpringLayout.Constraints(); 

        // Create a Spring object for y value for b1 and b2 
        Spring yPadding = Spring.constant(20); 

        // Set (10, 20) for (x, y) for b1 
        b1c.setX(Spring.constant(10)); 
        b1c.setY(yPadding); //ww w .j  a  v a  2s. c  o m

        // Set (150, 20) for (x, y) for b2 
        b2c.setX(Spring.constant(150)); 
        b2c.setY(yPadding); 

        // Use the Constraints object while adding b1 and b2 
        contentPane.add(b1, b1c); 
        contentPane.add(b2, b2c); 

        frame.pack(); 
        frame.setVisible(true);  
    } 
}