What is Auto Boxing?

Autoboxing is the automatic conversion that the Java compiler makes between the primitive types and their corresponding object wrapper classes.

Example 1.Integer nineC = 9;

Example 2.Integer ten = new Integer(10);
ten++;//allowed. Java does had work behind the screen for us

Auto Boxing helps in saving memory by reusing already created Wrapper objects. Auto Boxing uses the static valueOf methods. However wrapper classes created using new are not reused.

Two wrapper objects created using new are not same object.

Integer nineA = new Integer(9);
Integer nineB = new Integer(9);
System.out.println(nineA == nineB);//false

Two wrapper objects created using boxing are same object.

Integer nineC = 9;
Integer nineD = 9;
System.out.println(nineC == nineD);//true