Best practice to look up Java Enum

Question

We have a REST API where clients can supply parameters representing values defined on the server in Java Enums.

So we can provide a descriptive error, we add this

Answer 1

The error message in IllegalArgumentException is already descriptive enough.

Your method makes a generic exception out of a specific one with the same message simply reworded. A developer would prefer the specific exception type and can handle the case appropriately instead of trying to handle RuntimeException.

If the intent is to make the message more user friendly, then references to values of enums is irrelevant to them anyway. Let the UI code determine what should be displayed to the user, and the UI developer would be better off with the IllegalArgumentException.