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

There are no Class literals for parameterized types, however there are Type objects that correctly define these types.

See java.lang.reflect.ParameterizedType - http://java.sun.com/j2se/1.5.0/docs/api/java/lang/reflect/ParameterizedType.html

Google's Gson library defines a TypeToken class that allows to simply generate parameterized types and uses it to spec json objects with complex parameterized types in a generic friendly way. In your example you would use:

Type typeOfListOfFoo = new TypeToken>(){}.getType()

I intended to post links to the TypeToken and Gson classes javadoc but Stack Overflow won't let me post more than one link since I'm a new user, you can easily find them using Google search