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

In Java int is a primitive data type while Integer is a Helper class, it is use to convert for one data type to other.

For example:

double doubleValue = 156.5d;
Double doubleObject  = new Double(doubleValue);
Byte myByteValue = doubleObject.byteValue ();
String myStringValue = doubleObject.toString();

Primitive data types are store the fastest available memory where the Helper class is complex and store in heep memory.

reference from "David Gassner" Java Essential Training.