Mudando de Jframe para Jpanel Dúvida

public class Ex_Layout extends JPanel {   
    public Ex_Layout() {   
    	
    	// ** 
    //	this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
           
      //  Container c = this.getContentPane();   
      
        GridBagConstraints cons = new GridBagConstraints();   
        GridBagLayout layout = new GridBagLayout();   
        this.setLayout(layout);