Java Bitshift Operation: error converting int to byte

Question

can someone tell me why the following code is throwing the compile error "cannot convert from int to byte"?

byte x = 2;  
byte y = (x >> 1);

I mean I clearly declared both x and y as bytes, and 'x >> 1' will evaluate to 1 i.e. still be in the range of a byte.
Also when I do something like

byte x = -2;  
System.out.println(x >>> 1);

I would expect 126 to be the outcome, because I shifted a 0 in the leftmost bit of b1111 1101, which is 0111 1110. But the console is printing '2147483647', so it looks like my byte has been converted to an integer before the 0 has been shifted in. Why is that? Please help me out.

The type of x >> 1 is int. Why? Because the language specification says so. — Marko Topolnik
– Marko Topolnik, Commented Nov 8, 2016 at 17:52

Nicolas Filotto · Accepted Answer · 2016-11-08 18:09:20Z

4

Simply because x >> 1 returns an int so you simply need to cast it explicitly to a byte as next:

byte y = (byte)(x >> 1);

Please also note that since it is an int operator (or long depending on the left-hand operant cf §15.19 from the specification), all its operands must be of type int which means that in your case x will be implicitly converted into an int too in other words x >> 1 is equivalent to (int)x >> 1

edited Nov 8, 2016 at 18:09

answered Nov 8, 2016 at 17:53

Nicolas Filotto

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