0x7FFFFFFF is 0111 1111 1111 1111 1111 1111 1111 1111 : all 1 except the sign bit.
(hash & 0x7FFFFFFF) will result in a positive integer.
0x7FFFFFFF is 0111 1111 1111 1111 1111 1111 1111 1111 : all 1 except the sign bit.
(hash & 0x7FFFFFFF) will result in a positive integer.