Question

In the Core Java Volume1 book there is a caution that say:

CAUTION: The right-hand side argument of the shift operators is reduced modulo 32
(unless the left-hand side is a long, in which case the right-hand side is reduced modulo 64).
For example, the value of 1 << 35 is the same as 1 << 3 or 8.

What exactly does this mean? also why 1 become 8, instead of being 0 after 35 left shifting?

many thanks

Answer 1

In many programming languages, shifting by more than the size of a numeric data type (32 bits for an int, 64 bits for a long) is undefined. On the other hand, Java defines it such that (n << d) is equivalent to (n << (d % 32)) where n is an int, and (n << d) is equivalent to (n << (d % 64)) where n is a long.

So, 1 << 35 is equivalent to 1 << (35 % 32), which equals 1 << 3 = 8.