code: @SafeVarargs
      public static <T> boolean addAll(Collection<? super T> c, T... elements) {
          boolean result = false;
          for (T element : elements)
              result |= c.add(element);
          return result;
      }
docs: Adds all of the specified elements to the specified collection.
  Elements to be added may be specified individually or as an array.
  The behavior of this convenience method is identical to that of
  <tt>c.addAll(Arrays.asList(elements))</tt>, but this method is likely
  to run significantly faster under most implementations.
  
  <p>When elements are specified individually, this method provides a
  convenient way to add a few elements to an existing collection:
  <pre>
  Collections.addAll(flavors, "Peaches 'n Plutonium", "Rocky Racoon");
  </pre>
  
  @param  <T> the class of the elements to add and of the collection
  @param c the collection into which <tt>elements</tt> are to be inserted
  @param elements the elements to insert into <tt>c</tt>
  @return <tt>true</tt> if the collection changed as a result of the call
  @throws UnsupportedOperationException if <tt>c</tt> does not support
  the <tt>add</tt> operation
  @throws NullPointerException if <tt>elements</tt> contains one or more
  null values and <tt>c</tt> does not permit null elements, or
  if <tt>c</tt> or <tt>elements</tt> are <tt>null</tt>
  @throws IllegalArgumentException if some property of a value in
  <tt>elements</tt> prevents it from being added to <tt>c</tt>
  @see Collection#addAll(Collection)
  @since 1.5