Question

Why does javac add values() and valueOf(String) methods to the enum type being defined? Wouldn’t it have been better that they were added to Enum class itself?

What I mean is, if I have some enum such as

enum FooEnum {ONE, TWO}

javac adds values() and valueOf(String) to FooEnum when compiling it. I find it a bit odd. What is the reason behind this?

Is it only to ensure type safety of the returned value/values or is there anything else? And if it’s for type safety alone, wouldn’t Generics have helped?

Answer 1

They’re static methods – how could they have been added to Enum? Static methods aren’t polymorphic. Additionally, what would the implementation have looked like in Enum, in your proposed scheme? Enum itself doesn’t know the values – only the concrete type does.