Generics are new in .NET 2.0.It is used to define a type
while leaving some details unspecified.Generics are the
replacement of "Objects" in .NET1.1
Generics reduces the run-time error and increases the
performance.

Generics provide the solution to a limitation in earlier 
versions of the common language runtime and the C# language 
in which generalization is accomplished by casting types to 
and from the universal base type Object. By creating a 
generic class, you can create a collection that is type-
safe at compile-time.increases the
performance.

Generica provide type parameters T for class , interfaces, 
delagates or methods.
                    By using generic type parameter T their 
is less need of boxing / un boxing in client code.

Example : public class Genericlist <T>{
}

Generics are an extremely useful feature that allows you to 
write type safe and efficient collection- and pattern-based 
code.

Generics allow you to create type-safe code without knowing
the final type you will be working with. In many instances, 
you want the types to have certain characteristics, in 
which case you place constraints on the type