JPanel Appears To Be Null

I've a JPanel declared as a field in a JFrame:

public static javax.swing.JPanel pane;
I initialize it in a method (Well, Netbeans' GUI builder does. :P)
pane = new javax.swing.JPanel(){
@Override
public void paint(Graphics g){
g.setColor(Color.BLACK);
g.drawArc(8, 6, 15, 15, 0, 90); /* This works. The panel and frame are displayed, the arc is drawn, &c. */
}
};

it works and all; the arc is drawn.I want to draw on it dynamically by instantiating its Graphics (I call the "public Graphics getGraphics()" method.). This has worked for me before, taking a JPanel's Graphics and drawing with it through a different method than public void paint(Graphics g); But when I do, it comes up with a NullPointerException. WAIT! Don't go rambling on about initializing the variable because I've gotten past that NPE newbie's blockade.public static void render(Something s) { /*This is in a different file altogether. pane is public, static so I can access it from here. That's not the problem.*/

JPanel jp = Frame.pane;
Graphics g = jp.getGraphics();
g.fillRect(s.x, s.y, 4, 4);
}

Upon further investigation:
Exception in thread "main" java.lang.NullPointerException
at physics.Renderer.render(Renderer.java:30) <-- This line is "JPanel jp = Frame.pane;"
at physics.Renderer.renderall(Renderer.java:24) <--This line calls public static void render(Something s)
at physics.Updater.update(Updater.java:47) <--Renderer is just a tool used by the Updater. Sounds like a game loop, right?
at physics.Physics.main(Physics.java:31) <-- The game loop.

it says that Line 30, making jp and pointing it to pane itself is the problem.

Conclusion:
-The JPanel in the JFrame is created, initialized and overrides a parent method.
-The JPanel is not initialized, meaning that it is null. There is obviously a problem.