Add colour and a button with null layout manager

package Awt1;
 
import java.awt.*;
import java.awt.event.*;
 
class Awt1 extends Frame {
	Button l=new Button("Hello");
 
	public Awt1() 
	{
		addWindowListener(new WindowAdapter() {
			                                  public void windowClosing(WindowEvent e) {
			                                                                        	dispose();
				                                                                        System.exit(0);
		                                                                            	}
	                                        	}
	                    );
	                    setLayout(null);//no layout manage
	}
 
	public static void main(String args[]) {
		System.out.println("Starting Awt1...");
		Awt1 mainFrame = new Awt1();
		mainFrame.setSize(400, 400);
		mainFrame.setTitle("Awt1");
		mainFrame.setVisible(true);
		mainFrame.setBackground(new java.awt.Color(0,0,255));
		Button bb=new Button("Hello");
		bb.setBounds(100,100,80,30);// setting button position  
		mainFrame.add(bb);
 
 
	}
}