java generic how to ensure type has specified annotation?

Question

I'm trying to create a generic class in android using Java but I want to make sure that the type would take specific classes with specific annotations like this: I have class Table with annotation @Entity

@Entity
public class Table{}

and the generic class should only accept objects that have the @Entity annotation

Answer 1

if you want to check class annotation you have to use Reflection
http://static.javadoc.io/org.reflections/reflections/0.9.10/org/reflections/Reflections.html getTypesAnnotatedWith is the function you need

final Reflections reflections = new Reflections(packagePrefix);
    final Set<Class<?>> namedClasses = reflections.getTypesAnnotatedWith(Named.class);
    for (final Class<?> namedClass : namedClasses) {

    }

Answer 2

Simple answer: not possible.

Annotations represent meta information that isn't available when constructing classes using generic type parameters.