Wrapper Classes

byte,int,short,char,boolean,long,float,double.
To wrap primitive into object form so that we can handle primitive just like objects.
Student s=new Student(); s.getMarks(); s.getInfo();
To define several utility methods for primitive. ex: 10 to string String s = Integer.toString(10);

AutoBoxing and Auto UnBoxing:

Introduced in 1.5 version.
In 1.4 version we cannot provide primitive value in place of wrapper object and in place of wrapper object we cannot provide wrapper object.
ArrayList l=new ArrayList();
l.add(10);
Boolean b=new Boolean(true) if(b){ }

This automatic conversion from primitive to Object is called as AutoBoxing and object to primitive is called AutoUnboxing.

 int autoBoxing=123;

 System.out.println(Integer.valueOf(autoBoxing));

 Integer autoUnBoxing = new Integer (23);

 System.out.println(autoUnBoxing.intValue ());

 String num = "123";

 int i = Integer.parseInt(num);

 System.out.println(i);

 Integer num1=123;

 String s1 = num1.toString ();

 System.out.println (s1);