Java doesn't allow arrays of inner classes for a generic class

Question

I know that you cannot create an array of a generic type, Instead you have to resort to a hack. (Given Java supports generic arrays, just not their creation, it is not clear to me why a hack is better than Java supporting creating generic arrays)

Instead of writing this

Map.Entry<K, V>[] entries = new Map.Entry<K, V>[numEntries];

you have to write this

@SuppressWarnings("unchecked")
Map.Entry<K, V>[] entries = (Map.Entry<K, V>) new Map.Entry[numEntries];

Unfortunately this doesn't work if you have an array of nested type of a generic

public class Outer<E> {
    final Inner[] inners = new Inner[16]; // Generic array creation

    class Inner {
    }
}

The best work around appears to be

@SuppressWarnings("unchecked")
final Inner[] inners = (Inner[]) Array.newInstance(Inner.class, 16);

Is this the most "elegant" solution?

---

I make seen Generic Array Creation Compilation Error From Inner Class but the solution here is worse IMHO.

Answer 1

Do the following:

@SuppressWarnings("unchecked")
final Inner[] inners = (Inner[])new Outer<?>.Inner[16];

The equivalent to your first example would have been new Outer.Inner[16] but this will isolate the unchecked cast and avoid the raw type.