Well, really their hand was forced because they needed to be able to specialize all of the array-of-primative types. It's not as much they saw the advantage as

Well, really their hand was forced because they needed to be able to specialize all of the array-of-primative types. It's not as much they saw the advantage as they couldn't imagine a language where you can't express `byte []`. But the point stands that they could have realized that `ArrayList <byte>` is almost as fundamental and created refied generics for user-defined types as well.