Why can a enum have a package-private constructor?

enums, java, package-private

Solution

The constructor actually isn't package-private... it's implicitly `private` the way interface methods are implicitly `public` even if you don't add the keyword.

The relevant section of the JLS (§8.8.3) states:

If no access modifier is specified for the constructor of a normal class, the constructor has default access.

If no access modifier is specified for the constructor of an enum type, the constructor is `private`.

It is a compile-time error if the constructor of an enum type (§8.9) is declared `public` or `protected`.

Problem

Original source