According to the specs J2SE 1.4.2 and 5.0:
KeyboardFocusManager.setDefaultFocusTraversalKeys(int id, Set keystrokes)
"Throws: IllegalArgumentException - .. if any Object in 
keystrokes is not an AWTKeyStroke"

However, the J2SE implementations 1.4.2 and 1.5.0 throw ClassCastException
instead of expected IllegalArgumentException.

The code sample below demonstrates the problem:
-------------- TestFT14.java -----------------
import java.awt.*;
import java.util.*;

public class TestFT14 {
    KeyboardFocusManager currentKFM = 
            KeyboardFocusManager.getCurrentKeyboardFocusManager();

    public static void main(String[] args) {
        new TestFT14().test();
    }

    private void test() {       
        AWTKeyStroke key = AWTKeyStroke.getAWTKeyStroke("ENTER");
        HashSet set = new HashSet();
        set.add(key);
        set.add(new Object());

        try {
            currentKFM.setDefaultFocusTraversalKeys(
                   KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, set);
        } catch(Exception e) {
            if (e instanceof IllegalArgumentException) {
                System.out.println("KFM: OKAY");
            } else {
                e.printStackTrace();
                System.out.println("KFM: unexpected " + e + " thrown instead of IAE");
            }
        }
    }
}
---------------------------------------------------
-------------- Output for 1.4.2 -------------------
e:\>c:\jdk1.4.2\bin\java -classpath . TestFT14
java.lang.ClassCastException
        at java.awt.KeyboardFocusManager.setDefaultFocusTraversalKeys(KeyboardFocusManager.java:952)
        at TestFT14.test(TestFT14.java:19)
        at TestFT14.main(TestFT14.java:9)
KFM: unexpected java.lang.ClassCastException thrown instead of IAE
---------------------------------------------------

###@###.### 2004-11-16 11:06:39 GMT