SpringBoot Autowired in hibernate constraintvalidator custom annotation returns nullexception

After looking around, I couldn't find any good solution to this.

My autowired didn't work as expected where it returns null. I've autowired this particular class in other classes and it works so it only doesn't work in constraintvalidator classes.

Error

java.lang.IllegalStateException: Failed to execute CommandLineRunner at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:798) ~[spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE] at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:779) ~[spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:322) ~[spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1237) ~[spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE] at com.Alex.Mains.JpaApplication.main(JpaApplication.java:21) ~[classes/:na] Caused by: org.springframework.transaction.TransactionSystemException: Could not commit JPA transaction; nested exception is javax.persistence.RollbackException: Error while committing the transaction at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:543) ~[spring-orm-5.2.7.RELEASE.jar:5.2.7.RELEASE] at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:743) ~[spring-tx-5.2.7.RELEASE.jar:5.2.7.RELEASE] at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:711) ~[spring-tx-5.2.7.RELEASE.jar:5.2.7.RELEASE] at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:632) ~[spring-tx-5.2.7.RELEASE.jar:5.2.7.RELEASE] at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:386) ~[spring-tx-5.2.7.RELEASE.jar:5.2.7.RELEASE] at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:118) ~[spring-tx-5.2.7.RELEASE.jar:5.2.7.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.7.RELEASE.jar:5.2.7.RELEASE] at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ~[spring-tx-5.2.7.RELEASE.jar:5.2.7.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.7.RELEASE.jar:5.2.7.RELEASE] at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:178) ~[spring-data-jpa-2.3.1.RELEASE.jar:2.3.1.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.7.RELEASE.jar:5.2.7.RELEASE] at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:95) ~[spring-aop-5.2.7.RELEASE.jar:5.2.7.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.7.RELEASE.jar:5.2.7.RELEASE] at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.2.7.RELEASE.jar:5.2.7.RELEASE] at com.sun.proxy.$Proxy93.save(Unknown Source) ~[na:na] at com.Alex.Mains.UserRepositoryCommandLineRunner.run(UserRepositoryCommandLineRunner.java:26) ~[classes/:na] at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:795) ~[spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE] ... 5 common frames omitted Caused by: javax.persistence.RollbackException: Error while committing the transaction at org.hibernate.internal.ExceptionConverterImpl.convertCommitException(ExceptionConverterImpl.java:81) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at org.hibernate.engine.transaction.internal.TransactionImpl.commit(TransactionImpl.java:104) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:534) ~[spring-orm-5.2.7.RELEASE.jar:5.2.7.RELEASE] ... 21 common frames omitted Caused by: javax.validation.ValidationException: HV000028: Unexpected exception during isValid call. at org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.validateSingleConstraint(ConstraintTree.java:186) ~[hibernate-validator-6.1.5.Final.jar:6.1.5.Final] at org.hibernate.validator.internal.engine.constraintvalidation.SimpleConstraintTree.validateConstraints(SimpleConstraintTree.java:62) ~[hibernate-validator-6.1.5.Final.jar:6.1.5.Final] at org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.validateConstraints(ConstraintTree.java:75) ~[hibernate-validator-6.1.5.Final.jar:6.1.5.Final] at org.hibernate.validator.internal.metadata.core.MetaConstraint.doValidateConstraint(MetaConstraint.java:130) ~[hibernate-validator-6.1.5.Final.jar:6.1.5.Final] at org.hibernate.validator.internal.metadata.core.MetaConstraint.validateConstraint(MetaConstraint.java:123) ~[hibernate-validator-6.1.5.Final.jar:6.1.5.Final] at org.hibernate.validator.internal.engine.ValidatorImpl.validateMetaConstraint(ValidatorImpl.java:555) ~[hibernate-validator-6.1.5.Final.jar:6.1.5.Final] at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForSingleDefaultGroupElement(ValidatorImpl.java:518) ~[hibernate-validator-6.1.5.Final.jar:6.1.5.Final] at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForDefaultGroup(ValidatorImpl.java:488) ~[hibernate-validator-6.1.5.Final.jar:6.1.5.Final] at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForCurrentGroup(ValidatorImpl.java:450) ~[hibernate-validator-6.1.5.Final.jar:6.1.5.Final] at org.hibernate.validator.internal.engine.ValidatorImpl.validateInContext(ValidatorImpl.java:400) ~[hibernate-validator-6.1.5.Final.jar:6.1.5.Final] at org.hibernate.validator.internal.engine.ValidatorImpl.validate(ValidatorImpl.java:172) ~[hibernate-validator-6.1.5.Final.jar:6.1.5.Final] at org.hibernate.cfg.beanvalidation.BeanValidationEventListener.validate(BeanValidationEventListener.java:116) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at org.hibernate.cfg.beanvalidation.BeanValidationEventListener.onPreInsert(BeanValidationEventListener.java:80) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at org.hibernate.action.internal.EntityInsertAction.preInsert(EntityInsertAction.java:227) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at org.hibernate.action.internal.EntityInsertAction.execute(EntityInsertAction.java:100) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:604) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at org.hibernate.engine.spi.ActionQueue.lambda$executeActions$1(ActionQueue.java:478) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at java.base/java.util.LinkedHashMap.forEach(LinkedHashMap.java:723) ~[na:na] at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:475) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:348) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:40) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:102) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at org.hibernate.internal.SessionImpl.doFlush(SessionImpl.java:1360) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:451) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at org.hibernate.internal.SessionImpl.flushBeforeTransactionCompletion(SessionImpl.java:3210) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at org.hibernate.internal.SessionImpl.beforeTransactionCompletion(SessionImpl.java:2378) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.beforeTransactionCompletion(JdbcCoordinatorImpl.java:447) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.beforeCompletionCallback(JdbcResourceLocalTransactionCoordinatorImpl.java:183) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.access$300(JdbcResourceLocalTransactionCoordinatorImpl.java:40) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.commit(JdbcResourceLocalTransactionCoordinatorImpl.java:281) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] at org.hibernate.engine.transaction.internal.TransactionImpl.commit(TransactionImpl.java:101) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final] ... 22 common frames omitted Caused by: java.lang.NullPointerException: null at com.Alex.Validations.EmailValidator.isValid(EmailValidator.java:26) ~[classes/:na] at com.Alex.Validations.EmailValidator.isValid(EmailValidator.java:1) ~[classes/:na] at org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.validateSingleConstraint(ConstraintTree.java:180) ~[hibernate-validator-6.1.5.Final.jar:6.1.5.Final]

UserService class

@Service
public class UserService {

    @Autowired
    private UserRepository userRep;

    public void addUser(User user) {
        userRep.save(user);
    }


    public void deleteUser(long userId) {
        userRep.deleteById(userId);
    }

    public List<User> retrieveAllUsers(){
        Iterable<User>temp =userRep.findAll();
        List<User>allUsers = null;
        temp.forEach(allUsers::add);
        return allUsers;
    }

    public boolean searchByEmail(String email) {
        return userRep.findByEmail(email);
    }

    public void updateUser(User user) {
        userRep.save(user);
    }
}

Annotation interface class

 @Target(ElementType.FIELD) 
    //When will the annotation be processed compilation, runtime etc
    @Retention(RetentionPolicy.RUNTIME)
    //Where is the logic
    @Constraint(validatedBy = EmailValidator.class)
    @Documented
    public @interface ValidEmail {

        //Error message
        String message() default "Invalid email";
        //Required for annotation
        Class<?>[] groups() default {};
        Class<? extends Payload>[] payload() default {};

    }

Annotation logic class

public class EmailValidator implements ConstraintValidator<ValidEmail, String> {

    @Autowired
    private UserService service;
    //Actual place to place the logic to check if the data is valid or not
    @Override
    public boolean isValid(String email, ConstraintValidatorContext context) {
        if (email == null) {
        return false;
        }

        List<User> users = service.retrieveAllUsers();
        if (users.size() > 0) { 
        return Pattern.matches("(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*|\"(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21\\x23-\\x5b\\x5d-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])*\")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\\[(?:(?:(2(5[0-5]|[0-4][0-9])|1[0-9][0-9]|[1-9]?[0-9]))\\.){3}(?:(2(5[0-5]|[0-4][0-9])|1[0-9][0-9]|[1-9]?[0-9])|[a-z0-9-]*[a-z0-9]:(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21-\\x5a\\x53-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])+)\\])", email)
                && service.searchByEmail(email);
        }

        else {
            return Pattern.matches("(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*|\"(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21\\x23-\\x5b\\x5d-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])*\")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\\[(?:(?:(2(5[0-5]|[0-4][0-9])|1[0-9][0-9]|[1-9]?[0-9]))\\.){3}(?:(2(5[0-5]|[0-4][0-9])|1[0-9][0-9]|[1-9]?[0-9])|[a-z0-9-]*[a-z0-9]:(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21-\\x5a\\x53-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])+)\\])", email);
        }
        }



    @Override
    public void initialize(ValidEmail validEmail) {
        validEmail.message();
    }

}

Comment From: snicoll

@fenzox thanks but you've asked the same question 10 min ago on Gitter and there is a StackOverflow question as well. To reduce the possibility of duplicating effort, I am going to close this now in the benefit of your SO question.