The following text from the constructor for Window(Frame owner)

     * @exception IllegalArgumentException if <code>gc</code>
     * is not from a screen device.

should probably say that the exception is thrown if the owner's
GraphicsConfiguration is not from a screen device.

The same change should probably be made for Window(Window owner)

The whole text for the Window(Frame owner) constructor is below:

    /**
     * Constructs a new invisible window with the specified
     * Frame as its owner.
     * <p>
     * If there is a security manager, this method first calls
     * the security manager's <code>checkTopLevelWindow</code>
     * method with <code>this</code>
     * as its argument to determine whether or not the window
     * must be displayed with a warning banner.
     *
     * @param owner the <code>Frame</code> to act as owner
     * @exception IllegalArgumentException if <code>gc</code>
     * is not from a screen device.
     * @exception java.lang.IllegalArgumentException if
     * <code>owner</code> is <code>null</code>. This exception
     * is always thrown when GraphicsEnvironment.isHeadless()
     * returns true.
     * @see java.awt.GraphicsEnvironment#isHeadless
     * @see java.lang.SecurityManager#checkTopLevelWindow
     */
    public Window(Frame owner) {
        this((GraphicsConfiguration)null);
        ownedInit(owner);
    }