What is the difference between an int and an Integer in Java and C#?

Question

I was reading More Joel on Software when I came across Joel Spolsky saying something about a particular type of programmer knowing the difference between an i

Answer 1

An int and Integer in Java and C# are two different terms used to represent different things. It is one of the the primitive data types that can be assigned to a variable that can store exactly. One value of its declared type at a time.

For example:

int number = 7;

Where int is the datatype assigned to the variable number which holds the value seven. So an int is just a primitive not an object.

While an Integer is a wrapper class for a primitive data type which has static methods. That can be used as an argument to a method which requires an object, where as int can be used as an argument to a method which requires an integer value, that can be used for arithmetic expression.

For example:

Integer number = new Integer(5);