Why i=i+j is not identical to i+=j

Question

I have below code

int i = 5;
long j = 5;

1. i = i + j; // Throwing an exception "Type mismatch: cannot convert from long to int"
2. i += j; // This working fine

As you can see 1st case throwing an exception but 2nd case working fine.

Why 2nd case working fine without throwing an any exception?

Answer 1

+= is a compound statement and Compiler internally casts it. Where as in first case direct statement and compiler cries.