669      * (<a href="Collection.html#optional-restrictions">optional</a>),

   669      * (<a href="Collection.html#optional-restrictions">optional</a>),

   670      *         or if the specified collection is null

   670      *         or if the specified collection is null

   671      * @see Collection#contains(Object)

   671      * @see Collection#contains(Object)

   672      */

   672      */

   673     public boolean removeAll(Collection<?> c) {

   673     public boolean removeAll(Collection<?> c) {

   674         return batchRemove(c, false);

   675         return batchRemove(c, false);

   675     }

   676     }

   676 

   677 

   677     /**

   678     /**

   678      * Retains only the elements in this list that are contained in the

   679      * Retains only the elements in this list that are contained in the

   689      * (<a href="Collection.html#optional-restrictions">optional</a>),

   690      * (<a href="Collection.html#optional-restrictions">optional</a>),

   690      *         or if the specified collection is null

   691      *         or if the specified collection is null

   691      * @see Collection#contains(Object)

   692      * @see Collection#contains(Object)

   692      */

   693      */

   693     public boolean retainAll(Collection<?> c) {

   694     public boolean retainAll(Collection<?> c) {

   694         return batchRemove(c, true);

   696         return batchRemove(c, true);

   695     }

   697     }

   696 

   698 

   697     private boolean batchRemove(Collection<?> c, boolean complement) {

   699     private boolean batchRemove(Collection<?> c, boolean complement) {

   698         final Object[] elementData = this.elementData;

   700         final Object[] elementData = this.elementData;