How can I detect integer overflow on 32 bits int?

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Math.addExact throws exception on overflow

Since Java 8 there is a set of methods in the Math class:

  • toIntExact(long)
  • addExact(int,int)
  • subtractExact(int,int)
  • multiplyExact(int,int)

…and versions for long as well.

Each of these methods throws ArithmeticException if overflow happens. Otherwise they return the proper result if it fits within the range.

Example of addition:

int x = 2_000_000_000;
int y = 1_000_000_000;
try {
    int result = Math.addExact(x, y);
    System.out.println("The proper result is " + result);
} catch(ArithmeticException e) {
    System.out.println("Sorry, " + e);
}

See this code run live at IdeOne.com.

Sorry, java.lang.ArithmeticException: integer overflow

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