How to declare a Typed Class in Java? [duplicate]

Question

I need to declare an instance of Map.class, but the Map is typed... So I need something like this:

Class <Map<String, String>> clazz = Map.class;

This line causes a compile error. What is the clean way of expressing this?

Answer 1

You can do it with casts.

Class<Map<String, String>> clazz = (Class<Map<String, String>>) (Object) Map.class;

This generates a warning but compiles.

The problem with it is that due to type erasure, the resulting object at runtime is no different from Map.class (it doesn't know about the type).

If you need an object that truly represents Map<String, String> you can look into using java.lang.reflect.Type or Guava's TypeToken.

Answer 2

import java.util.*;

public class Test{
  public static void main(String [] args){
   Class <Map> clazz = Map.class;
   System.out.println(clazz);
  }
}

will print

interface java.util.Map