相同泛型类型的泛型数组的泛型类

Question

I have a method signature like

public <T extends SomeClass> T[] findAll(Class<T> oClass, String condition)

But I'm not sure how I can create that T[] type from Class<T> . I've tried using a Collection<T> but I cannot cast (T[]) collection.toArray() and Array.newInstance(Class<?>, int) asks for an array class (ie T[] ) already, which is of no use and redundant.

Also, obvisously, new T[n] does not work.

I would presume it's something easy, but I'm numb for the solution right now :)

Thanks.

Answer 1

newInstance does not ask for an array class, it asks for the component type. It will work fine, albeit with the usual problems with unchecked casts and generic arrays.

T[]  myArr = (T[]) Array.newInstance(oClass, length);

But why mix arrays and Generics at all? It'll just lead to headaches. Use something from the Collections API, like List .