code: public static Class<?> getSubclassInScope(final Class<?> scopeClass) {
  		final String callerClass = Thread.currentThread().getStackTrace()[3].getClassName();
  		try {
  			final Class<?> candidateClass = Class.forName(callerClass, false, Thread.currentThread().getContextClassLoader());
  			if(!scopeClass.isAssignableFrom(candidateClass)) {
  				return null;
  			}
  			return candidateClass;
  		} catch (final ClassNotFoundException e) {
  			throw new IllegalStateException("The class should always exist",e);
  		}
  	}
docs: TODO: Relax this constraint, it should be possible to do it from
  named-inner classes.
  
  @param scopeClass
  the parent class from which to retrieve the subclass in the
  scope.
  
  @return the subclass of the specified that is within the scope if found,
  {@code null} otherwise.