Bit calculation on long argument overflows as if it were int

Question

Could someone explain me why the following computation overflows?

938372878L | (1 << 31) //results to -1209110770

It behaves as if the number were integer.

http://stackoverflow.com/questions/25556017/how-to-use-the-unsigned-integer-in-java-8 — Richard Chambers, Oct 26 '15 at 13:10

score 4 · Accepted Answer · answered Oct 26 '15 at 13:02

4

1 is an int literal, which is why (1 << 31) overflows. You should change it to 1L for it to be treated as long :

938372878L | (1L << 31)

This results in

3085856526

answered Oct 26 '15 at 13:02

Eran

@RichardChambers What do you mean? Java doesn't have unsigned long. – Eran Oct 26 '15 at 13:08

1 Answers1