#
MathAbsoluteNegative

Math.abs does not always give a non-negative result. Please consider other methods for positive numbers.

*Alternate names: MathAbsoluteRandom*

## The problem

`Math.abs`

returns a negative number when called with the largest negative number.

Example:

```
int veryNegative = Math.abs(Integer.MIN_VALUE);
long veryNegativeLong = Math.abs(Long.MIN_VALUE);
```

When trying to generate positive random numbers or fingerprints by using
`Math.abs`

around a random positive-or-negative integer (or long), there will a
rare edge case where the returned value will be negative.

This is because there is no positive integer with the same magnitude as
`Integer.MIN_VALUE`

, which is equal to `-Integer.MAX_VALUE - 1`

. Floating point
numbers donâ€™t suffer from this problem, as the sign is stored in a separate bit.

Instead, one should use random number generation functions that are guaranteed
to generate positive numbers:

```
Random r = new Random();
int positiveNumber = r.nextInt(Integer.MAX_VALUE);
```

or map negative numbers onto the non-negative range:

```
long lng = r.nextLong();
lng = (lng == Long.MIN_VALUE) ? 0 : Math.abs(lng);
```

## Suppression

Suppress false positives by adding the suppression annotation `@SuppressWarnings("MathAbsoluteNegative")`

to the enclosing element.