wrapper class

[Nadeem Malik]

Plzz tell me why we use wrapper classes.
if this is possible:
int a = 10;
then why should we use this:
Integer a = new Integer(10);

[Paul Selby]

The two things I would name are the convenience of constants and methods.
The constants have things like min and max values, NAN (not a number), and postive & negative infinity; depending on the wrapper.
For the primitives, the methods are generally to do with conversions.

[John Wetherbie]

Another reason you may want to use the wrapper classes is if you want to use something other than an array. The collections of the Collections API (List, Set, etc) only take objects.
John