Java on the Mac -- problem

[Hegemony Cricket]

Trying to run Java programs on the Mac (OS X 10.2.8, G4). From the
command line, any time my program tries to pop up a window, nothing
appears. I just get a "wait" cursor. Thought it was some configuration
problem with the program I was writing, but I get the same problem with
even this simple program:

import java.awt.*;

public class test
{
public static void main( String[] args )
{
Frame f = new Frame();
f.setSize( new Dimension( 500, 500 ) );
f.setVisible( true );
}
}
Any ideas?
--Mark