Why is this an issue?

Java 21 introduces the new method Math.clamp(value, min, max) that fits a value within a specified interval. Before Java 21, this behavior required explicit calls to the Math.min and Math.max methods, as in Math.min(max, Math.max(value, min)).

If min > max, Math.clamp throws an IllegalArgumentException, indicating an invalid interval. This can occur if the min and max arguments are mistakenly reversed.

Note that Math.clamp is not a general substitute for Math.min or Math.max, but for the combination of both. If value is the same as min or max, using Math.clamp is unnecessary and Math.min or Math.max should be used instead.

How to fix it

• If 2nd argument > 3rd argument, use Math.clamp(value, min, max) instead of Math.clamp(value, max, min).
• If value is the same as min, fix the logic or use Math.min(value, max) instead.
• If value is the same as max, fix the logic or use Math.max(min, value) instead.
• If min is the same as max, fix the logic because Math.clamp(value, x, x) will always return x.

Code examples

Noncompliant code example

Math.clamp(red, 255, 0); // Noncompliant, [255,0] is not a valid range

Compliant solution

Math.clamp(red, 0, 255); // Compliant

Noncompliant code example

Math.clamp(red, red, 255); // Noncompliant, use Math.min(red, 255)

Compliant solution

Math.min(red, 255); // Compliant

Noncompliant code example

Math.clamp(red, 0, red); // Noncompliant, use Math.max(red, 0)

Compliant solution

Math.max(red, 0); // Compliant

Resources

• Java Documentation - Math.clamp