How do I make a JFrame a certain size, not including the border?

Question

I have a JFrame that I've set to a certain size, using setBounds. However, that makes the window, including the borders, that size (which in hindsight makes complete sense). But what I want is for the size of the window it be, say, 800x600 plus the borders. This is important because I'm drawing to a Graphics object from the BufferStategy from the JFrame, but I've been drawing underneath the title bar when using a y value of less than about 20. I imagine different OSs (or even different OS settings) can have different thickness borders, too. I thought the borders were just tacked on a window afterwards, but this doesn't seem to be the case.

So, how do I make the space inside the borders a certain size, regardless of the thickness of the borders? Also, to make my life easier, how do I make point 0, 0 be the top left corner of the viewable contents of the frame?

By the way, using setUndecorated presents it's own problems, so I'm not trying that at the moment.

Answer 1

1. Set a preferred size for the content pane.
2. Pack the frame.
3. Job done.

E.G.

import java.awt.*;
import javax.swing.*;

class FixedSizeContent {
    public static void main(String[] args) {
        SwingUtilities.invokeLater( new Runnable() {
            public void run() {
                JFrame f = new JFrame("Fixed size content");
                f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
                Container c = f.getContentPane();
                c.setBackground(Color.YELLOW);
                // adjust to need.
                Dimension d = new Dimension(400,40);
                c.setPreferredSize(d);
                f.setResizable(false);
                f.pack();
                f.setVisible(true);
            }
        });
    }
}

Answer 2

let the drawing component report the size of the graphic as its pref

 @Override
 public Dimension getPreferredSize() {
      return new Dimension(myDrawing.getWidth(), myDrawing.getHeight());  
 } 

then follow @Andrew's bullets 2 and 3