Following method signature is defined in EntityGraph<T> interface
    /**
     * Add additional attributes to this entity graph that
     * correspond to attributes of subclasses of this EntityGraph's
     * entity type.  ...
    **/
public <T> Subgraph<? extends T> addSubclassSubgraph(Class<? extends T>
type);
Should the correct signature be
   public <S extends T> Subgraph<S> addSubclassSubgraph(Class<S> type);
Otherwise, the current signature <T> will hide
Regards --
Pinaki Poddar
Chair, Apache OpenJPA Project           
http://openjpa.apache.org/
JPA Expert Group Member
Application & Integration Middleware