Enum.valueOf throws a warning for unknown type of class that extends Enum?

Question

Give this:

Class enumClass = ...; // being passed in from a constructor
Enum e = Enum.valueOf(enumClass, aString); // produces a warnin         


        

Answer 1

If you think about what has to happen inside valueOf, you'll realize that your code cannot possibly work as written. Enum.valueOf needs as an argument an instance of an actual enum class; it then simply iterates through the values() for that class looking for a match.

Because of type erasure, generics won't work in your code. No actual type is being passed into Enum.valueOf.