Class Loading.Basic Question

Question

Hi,
I wrote a small piece of code and it is running fine.
     Enumeration enP = lP.getNameList();
     int i=0;
     while (enP.hasMoreElements()) {
          Object nE = enP.nextElement();
          String nV = nE.toString();
          System.out.println(nV);
I am in doubt,because as far as I know Enumeration is an interface as sucj an interface it is not supposed to have code. So, my question is which class is in fact been used by the program?

Answer 1

All you can know it that whatever class it is, it
implements the Enumeration interface. Well that's not really true. If you're really dying to
now what type it truly is, just print out its
class:Enumeration enP = lP.getNameList();
System.out.println( enP.getClass() );
That code shows what the class is on a specific version of a specific vendor's library. If you try to rely on that information, don't be surprised if it's a different class in another vendor's library or even the next version of the same vendor's library.
The truth is you really don't know what class of object a reference will point to when you write the code, at least if the reference type is non-final.