[Class]Ridiculous question

I have a class sosaIndex() that takes one parameter sosaRoot ; in this class
I have a contructor (method sosaIndex) that on instanciation calls a method
setIndexation based on sosaRoot.

When the first time I instancie to create an object called "aa" I have
this :
sosaIndex aa=sosaIndex(sosaRoot);

Now if I change the sosaRoot I can use :

(1) aa.setRoot(sosaRoot) if this method is part of class sosaIndex to change
the sosaRoot of the object "aa" instanciated.
and after this :
aa.setIndexation(sosaRoot)
to finish the job and eventually get my object "aa" up-todate,

but Java does not say anything wrong if I do again :

(2) sosaIndex aa=sosaIndex(sosaRoot);
I mean instancie a new object with the SAME NAME "aa".

Anything wrong with method (2) and what happens to the first
instanciation "aa" ?
Thanks.
.