Call to

 java.awt.KeyboardFocusManager.setDefaultFocusTraversalPolicy(FocusTraversalPolicy defaultPolicy)

affects already created components, though the spec says:

        /**
         * Note: this call doesn't affect already created components as they have
         * their policy initialized. Only new components will use this policy as
         * their default policy.
         **/

Please see the following code sample:

----

import java.awt.*;

public class Test {

    public static void main(String[] args) {
        
        KeyboardFocusManager currentKFM = KeyboardFocusManager.getCurrentKeyboardFocusManager();
        FocusTraversalPolicy defaultFTP = currentKFM.getDefaultFocusTraversalPolicy();
        ContainerOrderFocusTraversalPolicy newFTP = new ContainerOrderFocusTraversalPolicy();

        Frame frame = new Frame();
        Window window = new Window(frame);

        /**
         * Note: this call doesn't affect already created components as they have
         * their policy initialized. Only new components will use this policy as
         * their default policy.
         **/
        currentKFM.setDefaultFocusTraversalPolicy(newFTP);
        FocusTraversalPolicy resultFTP = window.getFocusTraversalPolicy();
        if (!resultFTP.equals(defaultFTP)) {
            System.out.println("Failure! FocusTraversalPolicy should not change");
        }
        
    }
}