Strange things can happen in Java:)

Question

Hi to all of you.I just wanted to point out something that I consider as very interesting and not to mention even strange... I will welcome any comment.
Ok now the thing is that I have written a code that defines one interface name it Relation. I have these many classes implementing it. In the Relation body I have declared :
public static final Vector all = new Vector();
And then in all of the constructors of my classes that implement Relation I have written:
all.add(this);
That was just one idea of mine and I did not think that it should work but actually it would... I got all the object that I created in just one vector and on a later point I could access them...
Now the strangest thing is that this vector is final and static and how the hell I am getting all of the instances set in it???
Any ideas?

Answer 1

but isn't final just saying that I can not change the so
defined variable which in my opinion is even defined
as a constant on a later point??? I need a micrometer to find the meaning of that sentence.
And what do u mean by [etc]If you have a declaration:
public final Vector bob = new Vector();it's bob that is final, not the Vector object. So bob always points to that Vector, but the Vector itself is not immutable, so you can add stuff to it.
If you don't want bob's content's changed, use java.util.Collections.unmodifiableList. I believe this'll work:
public final List bob = Collections.unmodifiableList(new Vector());Now you have a field, bob, which points to an empty list that will remain empty forever.
And one more question is it ok if we instanciate
things in interface as I have done with the vector???Still waiting on that micrometer, sorry.