How do you find out the REAL size of a JFrame?

I have a 开发者_运维技巧JFrame which is maximized (frame.setExtendedState(JFrame.MAXIMIZED_BOTH)).

I want to find out the size it is now extended to, but frame.getSize() returns a size of (0, 0).

The frame won't have the maximized size until you make it visible. So your basic code would be:

frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
frame.setVisible(true);
System.out.println(frame.getSize());

Using setExtendedState I got output in jframe java.awt.Dimension[width=408,height=334]. Please check your code.