Java has a constant
Ruby automatically "upgrades" the number (FixNumb -> BigNum) to hold the value provided, but the minimal value before the upgrade is:
FIXNUM_MIN = -(2**(0.size * 8 -2))
0.size gives the number of bytes used to store the number, so we need to multiply it by 8, to get bits and substract 2 bits.
2 bits is for: