Question

Need some inputs:

Lets say i have N ArrayList and in each i am adding foo() object.

Foo foo = new Foo()

A.add(foo);

B.add(foo);

N.add(foo);

Now modification done on any one foo() object will reflect in all the other arraylist?

1. If YES WHY? and

2. whether this behaviour can also be achieved using any other collection like Vector etc…?

3. IF i make foo as null will it reflect in all arraylist?

Answer 1

1. Yes, because all lists only contain a reference to the same objects
2. Yes, all collections work like that
3. No, because you can only set a reference to null, and each list has a copy of the reference.