src/java.desktop/share/classes/javax/swing/plaf/LayerUI.java

@@ -728,10 +728,19 @@
      * which is inherited from {@code JLayer}'s base classes.
      * <p>
      * This method is to be overridden instead of {@code JLayer.imageUpdate}.
      * <p>
      * <b>Note:</b> This method is usually called <b>not</b> on the Event Dispatching Thread.
+     *
+     * @param img the image being observed
+     * @param infoflags see imageUpdate for information
+     * @param x the x coordinate
+     * @param y the y coordinate
+     * @param w the width
+     * @param h the height
+     * @param l a {@code JLayer} component
+     * @return false if the infoflags indicate that the image is completely loaded; true otherwise
      */
     public boolean imageUpdate(Image img, int infoflags, int x, int y, int w, int h, JLayer<? extends V> l) {
         return l.imageUpdate(img, infoflags, x, y, w, h);
     }
 }