i want to change jpanel background color by clicking on buttons

ButtonFrame()
{
  jp=new JPanel();
  btn1=new JButton("Green button");
  btn2=new JButton("Yellow button");
  add(jp);
  setTitle("change background color");
  setSize(400,300);
}
public void actionPerformed(ActionEvent e)
{
  if(e.getSource()==btn1)
   setBackground(new Color(Color.GREEN));
  //same for others
}