autoboxing is that the conversion of primitive data types 
into wrapper class objects automatically.By using generic 
types of java 1.5,we an acheive it easily.By declaring, the 
collection classes as shown below we can do it.
HashSet<Integer> hs=new HashSet<Integer>();
hs.add(1);
hs.add(2);
Iterator it=hs.iterator(0;
while(it.hasNext())
System.out.println(it.next());

In case of autoboxing directly the value of the constructor
assign to a variable.i.e object of wrapper class directly
assign to a variable.but it is only possible in case of 1.5
version.
Ex:public class X
{public static void main(String a[])
  {Integer i1=new Integer("20");
   Integer i2=new Integer("20");
    int m1=i1;
    int m2=i2;
    S.o.p(m1+m2);o/p-20

auto boxing:-
The process of conversion of primitive data type into wraper
class object into AUTOMATICALLY is called Auto boxing.
By using generic types of java 1.5,we an acheive it
easily.By declaring, the collection classes as shown below
we can do it.
EX:

HashSet<Integer> hs=new HashSet<Integer>();
hs.add(1);
hs.add(2);
Iterator it=hs.iterator();
while(it.hasNext())
{
  
System.out.println(it.next());
}
(Note: original it.next() returns object but here
System.out.println print primitive datatypes.