<dependency> <groupId>org.hibernate.validator</groupId> <artifactId>hibernate-validator-gwt</artifactId> <version>6.0.17.Final</version> </dependency> public class TechnologyPrinciple { private String name; private String description; private boolean status; // ... } @GwtValidation(TechnologyPrinciple.class) public interface ValidationService extends Validator { } ValidatorFactory factory = Validation.buildDefaultValidatorFactory(); ValidationService validationService = GWT.create(ValidationService.class); validationService.init(factory); TechnologyPrinciple techPrinciple = new TechnologyPrinciple(); techPrinciple.setName(null); techPrinciple.setStatus(false); Set<ConstraintViolation<TechnologyPrinciple>> violations = validationService.validate(techPrinciple); for (ConstraintViolation<TechnologyPrinciple> violation : violations) { String errorMessage = violation.getMessage(); System.out.println(errorMessage); }