extensions/assistedinject/src/com/google/inject/assistedinject/FactoryModuleBuilder.java
public <T> FactoryModuleBuilder implement(Class<T> source, Class<? extends T> target) {
    return implement(source, TypeLiteral.get(target));
  }
public <T> FactoryModuleBuilder implement(Class<T> source, Class<? extends T> target) {
    return implement(source, TypeLiteral.get(target));
  }
See the factory configuration examples at {@link FactoryModuleBuilder}.