package com.zetcode; import javax.validation.ConstraintViolation; import javax.validation.Validation; import javax.validation.Validator; import javax.validation.ValidatorFactory; import javax.validation.constraints.Positive; import java.util.List; import java.util.Set; class Data { private List<@Positive Integer> values = List.of(2, 3, 4, 5, -4, 3); } public class PositiveValues { public static void main(String[] args) { var data = new Data(); ValidatorFactory factory = Validation.buildDefaultValidatorFactory(); Validator validator = factory.getValidator(); Set> cvs = validator.validate(data); System.out.println(cvs.size()); for (ConstraintViolation cv : cvs) { System.out.printf("%s: %s%n", cv.getPropertyPath(), cv.getMessage()); } } }