Regarding vector

> v.length

... which does not even exist

> and v.size()

... which only gives the number of elements added, not the internal size.

If you're really interested in what happens in a Vector, you can try this:

import java.util.*;

public class Veccy extends Vector {

public Veccy(int a, int b) {

super(a, b);

}

public static void main(String[] args) {

Veccy v = new Veccy(5, 10);

v.add("a");

v.add("b");

v.add("c");

v.add("d");

v.add("e");

System.out.println(v.elementData.length);

}

}

quittea at 2007-7-8 22:07:39 >

> see....if u add sixth element v.size() will return size as 6.....

Yes ...

> Now the statement (Veccy v = new Veccy(5, 10);) says

> OS that he will create 5 objects

This statement does not create any objects besides the Vector (and its internal fields).

> and if i add sixth element please reserve me 10 more spaces to me....

Right ... In general, it means "each time there's not enough space for a new element, do not only reserve 1 new place but 10 in a single step" (cause this is more efficient).

> Now, when u add 6th element the OS has declared 10 spaces for you

15 spaces as a total, in this case. And the OS is not necessarily involved directly to this step, as the JVM is the first address to talk to.

> but only after u enter 6th element it will assign 6th place for your element....

Yes ...

> rest 9 places you cannot claim....

Of course you can ?by adding more objects.

> It is similar to the fact

> that when you declare any object and print it's size

> it returns 0.....only when you define that object OS

> reserves apace for it....thus giving you actual size

I'm not sure whether you got the difference between the result of a call to size() and the internal space allocated by the Vector, which is >= size(). Typically, if you create a Vector instance without giving an explicit initial size, there's a default space of 10 elements reserved.

quittea at 2007-7-8 22:07:39 >