The javadoc comments for the following serialized fields in java/awt/Window.java
should have javadoc in /** ...*/ style, not /*...*/:
...

    /*
     * The opacity level of the window
     *
     * @serial
     * @see #setOpacity(float)
     * @see #getOpacity()
     * @since 1.7
     */
    private float opacity = 1.0f;

    /*
     * The shape assigned to this window. This field is set to {@code null} if
     * no shape is set (rectangular window).
     *
     * @serial
     * @see #getShape()
     * @see #setShape(Shape)
     * @since 1.7
     */
    private Shape shape = null;
...

Otherwise all of the above does not exist in Serialized Form javadoc.