I have (what I thought was) a straightforward BufferStrategy for a JFrame. It is created like so:
// Buffer
container.createBufferStrategy(2);
The frame needs to be displayable when you call createBufferStrategy. Also as camickr has pointed out you need to call it from the EDT.
One way to ensure this is to extend JFrame and override addNotify:
class MyFrame extends JFrame {
public void addNotify() {
super.addNotify();
// Buffer
createBufferStrategy(2);
strategy = getBufferStrategy();
}
}