bit manipulation - Why does bitwise AND of two short values result in an int value in Java?

Question

short permissions = 0755;
short requested = 0700;
short result = permissions & requested; 

I get a compiler error:

error possible loss of precision
found   : int
required: short

If I'm not totally wrong the result of binary AND is as long as the longest operand. Why is the result an integer?

Would there be a performance hit, if I would cast to short?

(short) permissions & requested

Answer 1

The short answer (hah!) is, binary numeric promotion.

• If any of the operands is of a reference type, unboxing conversion (§5.1.8) is performed. Then:
• If either operand is of type double, the other is converted to double.
• Otherwise, if either operand is of type float, the other is converted to float.
• Otherwise, if either operand is of type long, the other is converted to long.
• Otherwise, both operands are converted to type int.