Integer vs int

initialization

Integer

Integer num1 = 1;
Integer num2 = new Integer(1);
nums == nums2; // false

Integer num1 = 1;
Integer num2 = 1;
num1 == num2; // true. constant way to create, then default don't create new address

Integer num1 = 100;
Integer num2 = 1000;
num1 == num2; // false, because number > 256

int

int num1 = 1;
int num2 = 1;

useful methods

Integer

// convert a string to integer
Integer.parseInt() 
num1 == num2; // false
num1.equals(num2);   // true

int

num1 == num2; // true