What is Auto Boxing and Auto Unboxing in java?

When Java automatically converts a primitive type like int into corresponding wrapper class object e.g. Integer than its called auto boxing because primitive is boxed into wrapper class while in opposite case is called unboxing, where an Integer object is converted into primitive int. All primitive types e.g. byte, short, char, int, long, float, double and boolean has corresponding wrapper class e.g. Byte, Short, Integer, Character etc. and participate in auto boxing and unboxing. Since whole process happens automatically without writing any code for conversion it’s called auto boxing and auto unboxing.

                This conversion or need of auto boxing comes into play when we use collection which is used to store the object type then if we give the value of type int, byte etc. then auto boxing automatically converts it into the corresponding wrapper class object.

ArrayList ar = new ArrayList();

Ar.add(1);  //Auto Boxing

Ar.add(1);  //Auto UnBoxing

int number = Ar..get(0); // unboxing