Enumeration Interface and vector Class

Question

I am deeply confused about the Enumeration interface an vector class. I know there aren't used for storing and searching now a days but still was interested in them.

Facts I know:

1. Vector class implements Enumeration interface and thus its method hasMoreElements() and nextElement().

2. Vector class has a method elements() that returns an object of Vector class therefore has its return type of Enumeration.

Thing I am Confused about:

Suppose Vector vec=new Vector(2,3); vec.elements().nextElement() gives me desired object whereas just vec.nextElement() is undefined though Vector class actually implements Enumeration Interface so why can't its object directly access the overridden methods.

Answer 1

The JAVA DOC of Vector class shows that implemented interfaces in this class are Serializable, Cloneable, Iterable<E>, Collection<E>, List<E>, RandomAccess

The Vector's elements() method signature is: public Enumeration<E> elements() calling Which returns an instance of implemented Enumeration as is evident from following source code:

public Enumeration<E> elements() {
        return new Enumeration<E>() {  // return implemented enumeration
            int count = 0;

            public boolean hasMoreElements() {
                return count < elementCount;
            }

            public E nextElement() {  // implementing nextElement
                synchronized (Vector.this) {
                    if (count < elementCount) {
                        return elementData(count++); 
                          // accessing vector elements data which 
                         //traverses an array of object
                    }
                }
                throw new NoSuchElementException("Vector Enumeration");
            }
        };
    }

Answer 2

Vecotr class does not implement Enumeration. Where did you see that, can you share source of you information.

public class Vector<E>
extends AbstractList<E>
implements List<E>, RandomAccess, Cloneable, java.io.Serializable

Further, none of the the class or interface implement or extend Enumeration interface.