How does guice's TypeLiteral work?

Question

How does Guice\'s TypeLiteral overcome the Java generic types erasure procedure?

It works wonders but how is this accomplished?

Answer 1

The trick that is used here is that the signatures of generic super types are stored in subclasses and thus survive erasure.

If you create an anonymous subclass new TypeLiteral>() {} Guice can call getClass().getGenericSuperclass() on it and get a java.lang.reflect.ParameterizedType on which exists a method getActualTypeArguments() to get List as an instance of ParameterizedType.