Why don't Java's +=, -=, *=, /= compound assignment operators require casting?

Question

Until today, I thought that for example:

i += j;

Was just a shortcut for:

i = i + j;

But if we try this:<

Answer 1

Very good question. The Java Language specification confirms your suggestion.

For example, the following code is correct:

short x = 3;
x += 4.6;

and results in x having the value 7 because it is equivalent to:

short x = 3;
x = (short)(x + 4.6);