private static class ArrayList in java.util.Arrays - Why?

In java.util.Arrays there is a private static class called "ArrayList" defined. It is only referred from Arrays.asList method.

What is the benifit of doing this? Why is java.util.ArrayList not referred instead?

Code below:

   /**
    * @serial include
    */
      private static class ArrayList<E> extends AbstractList<E>
implements RandomAccess, java.io.Serializable