Need reviewer: JDK 8 CR for Support Integer overflow

Eamonn McManus eamonn at
Fri Feb 3 17:52:36 UTC 2012

My initial remarks:

In negateExact, the condition x == -x should be faster to evaluate than x
== Integer.MIN_VALUE and reflects the intent just as well.

In addExact and subtractExact, I would be inclined to implement the int
versions using long arithmetic, like this:

long lr = x + y;
int r = (int) lr;
if (r == lr) {
  return r;
} else {

I would use this technique of cast-and-compare in the int multiplyExact
instead of comparing against MIN_VALUE and MAX_VALUE, and especially in

I agree with Stephen Colebourne that brief implementation comments would be
useful. But I disagree with his proposed further methods in Math
(increment, decrement, int+long variants), which I don't think would pull
their weight.


On 2 February 2012 12:15, Roger Riggs <Roger.Riggs at> wrote:

> There is a need for arithmetic operations that throw exceptions
> when the results overflow the representation of int or long.
> The CR is 6708398: Support integer overflow <**
> bugdatabase/**id=6708398<>
> >
> Please review this webrev <**
> 7Erriggs/CR6708398/webrev/<>>
> to add static methods in java.lang.Math
> to support addExact(), subtractExact(), negateExact(), multiplyExact(),
> and toIntExact() for int and long primitive types.
> Thanks, Roger Riggs

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