How does Java bit shift operator (>>>) work?

Question

The output I calculated from right shifting the 2's complement of 20 and then converting the result to decimal does not match the output. Why does the code below generate such unexpected output?

class OperatorExample{  
    public static void main(String args[]){  

        System.out.println(-20>>>2);  
    } 
}

output: 1073741819

Did you know you were using an *unsigned* bit shift operator? — Scott Hunter, Jun 24 '19 at 15:26
Check this answer: https://stackoverflow.com/questions/2811319/difference-between-and — R.A, Jun 24 '19 at 15:29
Try this. https://docs.oracle.com/javase/tutorial/index.html — WJS, Jun 24 '19 at 15:33

score 2 · Accepted Answer · answered Jun 24 '19 at 15:27

The calculation is:

Take -20:

jshell> Integer.toBinaryString(-20)
$1 ==> "11111111111111111111111111101100"

Shift it right by 2, which removes the last two zeros:

jshell> Integer.toBinaryString(-20 >>> 2)
$2 ==> "111111111111111111111111111011"

And convert it to decimal:

jshell> 0b111111111111111111111111111011
$3 ==> 1073741819

How does Java bit shift operator (>>>) work?

1 Answers1