JDk8 add methods such as add/subtract/multiply/increment/decrement/Exact etc to throw ArithmeticException if it the result overflows.

The code:

Hacker's Delight

Hacker's Delight: The Basics

The Aggregate Magic Algorithms, 26 bit twiddling algorithms from Hank Dietz and others

Bit Twiddling Hacks, by Sean Anderson

The code:

public static long addExact(long x, long y) { long r = x + y; // HD 2-12 Overflow iff both arguments have the opposite sign of the result if (((x ^ r) & (y ^ r)) < 0) { throw new ArithmeticException("long overflow"); } return r; } public static long subtractExact(long x, long y) { long r = x - y; // HD 2-12 Overflow iff the arguments have different signs and // the sign of the result is different than the sign of x if (((x ^ y) & (x ^ r)) < 0) { throw new ArithmeticException("long overflow"); } return r; } public static int multiplyExact(int x, int y) { long r = (long)x * (long)y; if ((int)r != r) { throw new ArithmeticException("integer overflow"); } return (int)r; } public static long multiplyExact(long x, long y) { long r = x * y; long ax = Math.abs(x); long ay = Math.abs(y); if (((ax | ay) >>> 31 != 0)) { // Some bits greater than 2^31 that might cause overflow // Check the result using the divide operator // and check for the special case of Long.MIN_VALUE * -1 if (((y != 0) && (r / y != x)) || (x == Long.MIN_VALUE && y == -1)) { throw new ArithmeticException("long overflow"); } } return r; } public static long incrementExact(long a) { if (a == Long.MAX_VALUE) { throw new ArithmeticException("long overflow"); } return a + 1L; } public static long negateExact(long a) { if (a == Long.MIN_VALUE) { throw new ArithmeticException("long overflow"); } return -a; } public static int floorDiv(int x, int y) { int r = x / y; // if the signs are different and modulo not zero, round down if ((x ^ y) < 0 && (r * y != x)) { r--; } return r; }

**Resources**Hacker's Delight

Hacker's Delight: The Basics

The Aggregate Magic Algorithms, 26 bit twiddling algorithms from Hank Dietz and others

Bit Twiddling Hacks, by Sean Anderson