7057770: (spec)Scrollbar spec should specify that unit increment & decrement...

7057770: (spec)Scrollbar spec should specify that unit increment & decrement functionality may not be present
Reviewed-by: alexsch

src/share/classes/java/awt/Scrollbar.java

@@ -715,6 +715,9 @@ public class Scrollbar extends Component implements Adjustable, Accessible {
      * The unit increment must be greater than zero.
      * Attepts to set the unit increment to a value lower than 1
      * will result in a value of 1 being set.
+     * <p>
+     * In some operating systems, this property
+     * can be ignored by the underlying controls.
      *
      * @param        v  the amount by which to increment or decrement
      *                         the scroll bar's value
@@ -752,6 +755,9 @@ public class Scrollbar extends Component implements Adjustable, Accessible {
      * scroll bar, generally through a mouse or keyboard gesture
      * that the scroll bar receives as an adjustment event.
      * The unit increment must be greater than zero.
+     * <p>
+     * In some operating systems, this property
+     * can be ignored by the underlying controls.
      *
      * @return      the unit increment of this scroll bar
      * @see         java.awt.Scrollbar#setUnitIncrement