Why is there no need to explicitly cast in case of integers?

Question

byte a=10;
byte b=20;

b=a+b;

In this case, I need to explicitly convert a+b to byte like this :

b=(byte)(a+b);

It's the same with short :

short x=23;
short y=24;

Otherwise it gives an error.

But in case of integers, it's not required to convert explicitly :

int p=7788;
int q=7668;

p=p+q;

This will work just fine.

Why is that?

We don't need to explicitly cast even in the case of long as well.

Answer 1

If you look at the JLS 4.2.2 Integer Operations, it states that the result of a numerical operation between two integral operands is an int or a long. Since there's no implicit cast from an int to byte or a short, you need an explicit cast.