The expression final double FEET_PER_INCH = (1/12);
will always set FEET_PER_INCH
to 0. This is because of integer division - neither operand is a floating-point value, so the floating point result is discarded.
To fix it, you could either cast the division, or change a number to a decimal.
Example:
final double FEET_PER_INCH = (double)(1/12);
// or
final double FEET_PER_INCH = 1.0/12;