@Override
public void collectConstraintDefinitions(ConstraintDefinitionBuilder constraintDefinitionContributionBuilder) {
Map<Class<?>, List<Class<?>>> customValidators = newHashMap();
// find additional constraint validators via the Java ServiceLoader mechanism
GetConstraintValidatorList constraintValidatorListAction = new GetConstraintValidatorList();
List<ConstraintValidator<?, ?>> discoveredConstraintValidators = run( constraintValidatorListAction );
for ( ConstraintValidator<?, ?> constraintValidator : discoveredConstraintValidators ) {
Class<?> constraintValidatorClass = constraintValidator.getClass();
Class<?> annotationType = determineAnnotationType( constraintValidatorClass );