optaplanner-core/src/main/java/org/optaplanner/core/config/domain/ScanAnnotatedClassesConfig.java
private void retainOnlyClassesWithDeclaredAnnotation(Set<Class<?>> classSet, Class<? extends Annotation> annotation) {
        classSet.removeIf(clazz -> !clazz.isAnnotationPresent(annotation));
    }
private void retainOnlyClassesWithDeclaredAnnotation(Set<Class<?>> classSet, Class<? extends Annotation> annotation) {
        classSet.removeIf(clazz -> !clazz.isAnnotationPresent(annotation));
    }
TODO We need unit test for this: annotation scanning with TestdataUnannotatedExtendedEntity