docs: public static boolean isConcrete(Type t)
    {
      if(t instanceof Class) {
        final Class<?> c = (Class<?>)t;
        return !c.isInterface() && !Modifier.isAbstract(c.getModifiers());
      }
  
      if(t instanceof ParameterizedType) {
        final ParameterizedType p = (ParameterizedType)t;
        return isConcrete(p.getRawType());
      }
  
      return false;
    }