Java .addExact()

The Math.addExact() method returns the sum of its arguments. It will throw an exception if the result overflows either int or long.

Syntax

Math.addExact(a, b)

Both parameters a and b must either be of type int or long.

An exception is thrown if either parameter is equal to Integer.MAX_VALUE, Long.MAX_VALUE, or the result exceeds type int or long.

Example

This following example returns the sum of two values with the .addExact() method:

// Main.java
public class Main {
  public static void main(String[] args) {
    int a = 575;
    int b = 209;
    System.out.println(Math.addExact(a, b));

    /*
    Overflow will occur if any one of the argument is
    Long.MAX_VALUE or Integer.MAX_VALUE.
    */
    long x = Long.MAX_VALUE;
    long y = 86712;
    System.out.println(Math.addExact(x, y));
  }
}

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This will produce the following output:

784
Exception in thread "main" java.lang.ArithmeticException: long overflow
        at java.base/java.lang.Math.addExact(Math.java:845)
        at Main.main(Main.java:13)

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