NullPointerException on g.drawString

[sonny kher]

I have a start method that looks something like this
void start(){

LayeredPane lp = new JLayeredPane();
lp.setvisible(true);
add(lp)
Graphics g = lp.getGraphics();
g.drawString("check", 20, 20);
}

This throws a NullPointerException, any action on lp.getGraphics returns a NullPointerException. I don't know why this is happening.
If I put the drawString inside paint(Graphics g)
everything else disappears and only the String shows.

[Dirk Schreckmann]

I suspect that you're trying to get a Graphics object from something that isn't actually being displayed before you get the Graphics object (but it's hard to tell exactly what you're doing as the code that you've posted has errors and is out of context). Consider:

import java.awt.Graphics ;
import javax.swing.JLayeredPane ;
 
public class Foo
{
  public static void main( String[] args )
  {
    JLayeredPane lp = new JLayeredPane() ;
    lp.setVisible(true);
    Graphics g = lp.getGraphics() ;
    System.out.println( g ) ;
  }
}

which prints null and

import java.awt.Graphics ;
import javax.swing.JFrame ;
import javax.swing.JLayeredPane ;
 
public class Foo
{
  public static void main( String[] args )
  {
    JLayeredPane lp = new JLayeredPane() ;
    JFrame f = new JFrame() ;
    f.getContentPane().add( lp ) ;
    f.setSize( 100 , 100 ) ;
    f.setVisible( true ) ;
    lp.setVisible( true ) ;
    try
    {
      Thread.sleep( 2000 ) ;
    }
    catch ( InterruptedException ex )
    {
    }
    
    Graphics g = lp.getGraphics() ;
    System.out.println( g ) ;
  }
}

which doesn't print null. Getting any ideas?