What is the difference between int and Integer? In Java

Question

Does it have something to do with objects?

Answer 1

In Java, int is a primitive data type while Integer is a Wrapper class.

1.Int, being a primitive data type has got less flexibility. We can only store the binary value of an integer in it.

2.Since Integer is a wrapper class for int data type, it gives us more flexibility in storing, converting and manipulating an int data.

3.Integer is a class and thus it can call various in-built methods defined in the class. Variables of type Integer store references to Integer objects, just as with any other reference (object) type.

Answer 2

Integer a = new Integer("456");      

// Casting not possible      
// int a = (int)"456";    

// Casting not possible      
// int c="456";  

// Casting possible using methods      
// from Integer Wrapper class      
int b = Integer.parseInt("456");

this line of codes should make it clear.

Answer 3

There are few more things to consider.
int - 4 bytes
Integer - 16 bytes

int - defaults to 0
Integer defaults to null - which is another problem, because you have to do null check's.

You can compare int's simply like int1 == int2
But for comparing Integers you have to use .equals methods.

Answer 4

Thanks for all the responses!