The specification states for FocusTraversalPolicy.getInitialComponent:
"Throws: IllegalArgumentException - if window is null"

However, J2SE 1.4.2 and 1.5 throw NPE instead IAE.

The following code sample demonstrates the problem:
--------------------- TestFTP.java ----------------------
import java.awt.*;

public class TestFTP {

    public static void main(String[] args) {
        new TestFTP().test();
    }

    private void test() {
        CustomFocusTraversalPolicy cftp =
                 new CustomFocusTraversalPolicy();
        try {
            cftp.getInitialComponent(null);
        } catch (IllegalArgumentException iae) {
        } catch (Exception e) {
            System.out.println("Unexpected exception thrown: " + e);
        }
    }

    private class CustomFocusTraversalPolicy extends FocusTraversalPolicy {
    
        public Component getComponentAfter(Container focusCycleRoot,
                                           Component aComponent) {
            return null;
        }
        
        public Component getComponentBefore(Container focusCycleRoot,
                                            Component aComponent) {
            return null;
        }
        
        public Component getDefaultComponent(Container focusCycleRoot) {
            return null;
        }
        
        public Component getFirstComponent(Container focusCycleRoot) {
            return null;
        }
 
        public Component getLastComponent(Container focusCycleRoot) {
            return null;
        }
    }
}
---------------------------------------------------------------------
------------------------ Output -------------------------------------
Unexpected exception thrown: java.lang.NullPointerException
---------------------------------------------------------------------
###@###.### 2005-2-03 15:47:00 GMT