Java: how do I get a class literal from a generic type?

Question

Typically, I\'ve seen people use the class literal like this:

Class cls = Foo.class;

But what if the type is generic, e.g. List?

Answer 1

You could use a helper method to get rid of @SuppressWarnings("unchecked") all over a class.

@SuppressWarnings("unchecked")
private static  Class generify(Class cls) {
    return (Class)cls;
}

Then you could write

Class> cls = generify(List.class);

Other usage examples are

  Class> cls;

  cls = generify(Map.class);

  cls = TheClass.>generify(Map.class);

  funWithTypeParam(generify(Map.class));

public void funWithTypeParam(Class> cls) {
}

However, since it is rarely really useful, and the usage of the method defeats the compiler's type checking, I would not recommend to implement it in a place where it is publicly accessible.