Enumeration , class

Question

I have this following code in my JSP
Enumeration en = session.getAttributeNames();
System.err.println("Enumeration is "+en.getClass());
gives me "java.util.Vector$1"
Why does it show vector, a lit confused
TIA

Answer 1

Enumeration is an interface.
java.util.Vector$1 is the class that is actually implementing the Enumeration interface.
It is not actually a Vector. The $1 means that this class is actually an anonymous inner class of Vector.
This is the code out of the Vector class that provides the enumeration.
public Enumeration elements() {
     return new Enumeration() {
         int count = 0;
         public boolean hasMoreElements() {
          return count < elementCount;
         public Object nextElement() {
          synchronized (Vector.this) {
              if (count < elementCount) {
               return elementData[count++];
          throw new NoSuchElementException("Vector Enumeration");
    }So you actually do have an object that implements the enumeration interface. It is just an anonymous inner class written inside the Vector class, so its classname displays as java.util.Vector$1.
Does that clear things up?
Cheers,
evnafets