Need help in Generic class

Adding some more meaning full part to the above post.
from generics we can acheive the typesafety.for example
Normal list: list.add(1);list.add("adfasdf"); this is valid but invalid in runtime. we are losing the type safety.
generics list: list l=new list();list.add(1);list.add("asd");----->this line will leads to compile time error.
this is one more advantage with generics.

generics is basically what was called in C Templates
the idea is to have a nontyped return value, just like object only it is actually a type, and could could actually be a multiType
lets say you have multiple products type
1. Fridge
2. Cars
you will create an abstract class called product that has all the bussiness modal like: weigth, Height,cost and so on
and create  class Fridge : Product and class Cars : Product
then when you will say :
List where T: Product
you will be able to call the List meaning that the items inserted are actually typeof(Fridge)
here is a nice tutorial
http://www.artima.com/intv/genericsP.html
happy coding