Hibernate Validation + Custom Constraint + java.lang.NullPointerException

Question

I'have been fighting with this for days, I've read all the discussions here but with no solution...

I have a custom constraint..

Unique.java

@Target({FIELD, METHOD})
@Retention(RUNTIME)
@Constraint(validatedBy = UniqueConstraintValidator.class)
public @interface Unique {

    String message() default "{src.main.resources}";

    Class<?>[] groups() default {};

    Class<? extends Payload>[] payload() default {};

    String property() default "id";

    Class<?> entity();

}

This is used by UniqueConstraintValidator.java

@Transactional
public class UniqueConstraintValidator implements ConstraintValidator<Unique, Serializable> {
    private static final Logger logger = Logger.getLogger(UniqueConstraintValidator.class);
    Session session;


    @Autowired
    private SessionFactory sessionFactory;

    protected Session getSession(){
    return sessionFactory.getCurrentSession();
}

    private Class<?> entityClass;
    private String uniqueField;

    public void initialize(Unique unique) {
        entityClass = unique.entity();
        uniqueField = unique.property();

    }

    @SuppressWarnings("rawtypes")
    public boolean isValid(Serializable property, ConstraintValidatorContext cvContext) {

        String query = String.format("from %s where %s = :field ", entityClass.getName(), uniqueField);
        List list = getSession().createQuery(query).setParameter("field", property).list();
        return list != null && list.size() == 0;
    }

}

Now, my model has this annotation where I need to validate the uniqueness of the field

@NotNull
@Unique(entity = Luce.class, property="numeroLuce")
@Column(name="numero_luce")
public int getNumeroLuce() {
    return numeroLuce;
}

public void setNumeroLuce(int numeroLuce) {
    this.numeroLuce = numeroLuce;
}

Now, i know the custom annotation won't work while updating an existing object, but now i need to understand how it works. Let's assume we want to add a new object.

When I try to save an already existing value, I got a correct validation error but if I want to save a valid object i got a java.lang.NullPointerException

EDITED this is the full stacktrace

    exception

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is javax.validation.ValidationException: HV000028: Unexpected exception during isValid call.
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:982)
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause

javax.validation.ValidationException: HV000028: Unexpected exception during isValid call.
    org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.validateSingleConstraint(ConstraintTree.java:286)
    org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.validateConstraints(ConstraintTree.java:133)
    org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.validateConstraints(ConstraintTree.java:91)
    org.hibernate.validator.internal.metadata.core.MetaConstraint.validateConstraint(MetaConstraint.java:83)
    org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraint(ValidatorImpl.java:547)
    org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForDefaultGroup(ValidatorImpl.java:487)
    org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForCurrentGroup(ValidatorImpl.java:451)
    org.hibernate.validator.internal.engine.ValidatorImpl.validateInContext(ValidatorImpl.java:403)
    org.hibernate.validator.internal.engine.ValidatorImpl.validate(ValidatorImpl.java:206)
    org.hibernate.cfg.beanvalidation.BeanValidationEventListener.validate(BeanValidationEventListener.java:137)
    org.hibernate.cfg.beanvalidation.BeanValidationEventListener.onPreInsert(BeanValidationEventListener.java:95)
    org.hibernate.action.internal.EntityIdentityInsertAction.preInsert(EntityIdentityInsertAction.java:214)
    org.hibernate.action.internal.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:92)
    org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:490)
    org.hibernate.engine.spi.ActionQueue.addResolvedEntityInsertAction(ActionQueue.java:195)
    org.hibernate.engine.spi.ActionQueue.addInsertAction(ActionQueue.java:179)
    org.hibernate.engine.spi.ActionQueue.addAction(ActionQueue.java:214)
    org.hibernate.event.internal.AbstractSaveEventListener.addInsertAction(AbstractSaveEventListener.java:324)
    org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:288)
    org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:194)
    org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:125)
    org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:206)
    org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:149)
    org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:75)
    org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:811)
    org.hibernate.internal.SessionImpl.persist(SessionImpl.java:784)
    org.hibernate.internal.SessionImpl.persist(SessionImpl.java:789)
    it.besmart.dao.AbstractDao.persist(AbstractDao.java:37)
    it.besmart.dao.LuceDaoImpl.saveLuci(LuceDaoImpl.java:33)
    it.besmart.service.LuceServiceImpl.saveLuci(LuceServiceImpl.java:33)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    java.lang.reflect.Method.invoke(Method.java:497)
    org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:302)
    org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
    org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
    org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
    org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281)
    org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
    org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:208)
    com.sun.proxy.$Proxy48.saveLuci(Unknown Source)
    it.besmart.controller.LuceController.saveLight(LuceController.java:87)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    java.lang.reflect.Method.invoke(Method.java:497)
    org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:222)
    org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
    org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:814)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:737)
    org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause

java.lang.NullPointerException
    it.besmart.validator.UniqueConstraintValidator.getSession(UniqueConstraintValidator.java:27)
    it.besmart.validator.UniqueConstraintValidator.isValid(UniqueConstraintValidator.java:44)
    it.besmart.validator.UniqueConstraintValidator.isValid(UniqueConstraintValidator.java:18)
    org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.validateSingleConstraint(ConstraintTree.java:283)
    org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.validateConstraints(ConstraintTree.java:133)
    org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.validateConstraints(ConstraintTree.java:91)
    org.hibernate.validator.internal.metadata.core.MetaConstraint.validateConstraint(MetaConstraint.java:83)
    org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraint(ValidatorImpl.java:547)
    org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForDefaultGroup(ValidatorImpl.java:487)
    org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForCurrentGroup(ValidatorImpl.java:451)
    org.hibernate.validator.internal.engine.ValidatorImpl.validateInContext(ValidatorImpl.java:403)
    org.hibernate.validator.internal.engine.ValidatorImpl.validate(ValidatorImpl.java:206)
    org.hibernate.cfg.beanvalidation.BeanValidationEventListener.validate(BeanValidationEventListener.java:137)
    org.hibernate.cfg.beanvalidation.BeanValidationEventListener.onPreInsert(BeanValidationEventListener.java:95)
    org.hibernate.action.internal.EntityIdentityInsertAction.preInsert(EntityIdentityInsertAction.java:214)
    org.hibernate.action.internal.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:92)
    org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:490)
    org.hibernate.engine.spi.ActionQueue.addResolvedEntityInsertAction(ActionQueue.java:195)
    org.hibernate.engine.spi.ActionQueue.addInsertAction(ActionQueue.java:179)
    org.hibernate.engine.spi.ActionQueue.addAction(ActionQueue.java:214)
    org.hibernate.event.internal.AbstractSaveEventListener.addInsertAction(AbstractSaveEventListener.java:324)
    org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:288)
    org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:194)
    org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:125)
    org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:206)
    org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:149)
    org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:75)
    org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:811)
    org.hibernate.internal.SessionImpl.persist(SessionImpl.java:784)
    org.hibernate.internal.SessionImpl.persist(SessionImpl.java:789)
    it.besmart.dao.AbstractDao.persist(AbstractDao.java:37)
    it.besmart.dao.LuceDaoImpl.saveLuci(LuceDaoImpl.java:33)
    it.besmart.service.LuceServiceImpl.saveLuci(LuceServiceImpl.java:33)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    java.lang.reflect.Method.invoke(Method.java:497)
    org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:302)
    org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
    org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
    org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
    org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281)
    org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
    org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:208)
    com.sun.proxy.$Proxy48.saveLuci(Unknown Source)
    it.besmart.controller.LuceController.saveLight(LuceController.java:87)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    java.lang.reflect.Method.invoke(Method.java:497)
    org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:222)
    org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
    org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:814)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:737)
    org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

I really cannot understand what I'm doing wrong, i know i'm a java noob, but everything looks to me correct.

I added a log in UniqueConstraintValidator to check if sessionFactory is null, but i'm getting

Session is org.hibernate.internal.SessionFactoryImpl@53911200

so, it's not null...

Thanks in advance

Are you using Spring Framework, right? Add it to the tags, please. — Slava Semushin, Dec 09 '15 at 21:36
Looks like `sessionFactory` is `null` and it wasn't auto wired. — Slava Semushin, Dec 09 '15 at 21:42
I don't know if it's null because the exception comes before my logger.. But, if sessionFactory is null, it means that is null also when trying to validate a correct value, right? But i'm not getting the exception in that case... PS i added the tag, thanks — MarioC, Dec 09 '15 at 21:49
please debug your code and check where the nullpointer exception occurs. — Si mo, Dec 10 '15 at 09:40
Thanks @Simo I'm trying to look form the exception, but everything doesn't give me a null pointer... sessionFactory is not null everywhere in the process — MarioC, Dec 10 '15 at 10:04
that is weird, ocurrs the nullpointer in the log while debugging? that can't be — Si mo, Dec 10 '15 at 10:06
added it, thanks, i put a logger to check for null values in every class of my project that is involved in the stacktrace — MarioC, Dec 10 '15 at 10:14
so the problem comes only when isValid is true, so it should go on and save the new Object... Clearly, if I comment the @Unique annotation, the object is saved normally... So it must be something that happens only after isValid is called... — MarioC, Dec 10 '15 at 13:42

score 1 · Answer 1 · edited May 23 '17 at 12:24

1

In this comment You will find answer.

JSR303 custom validators being called twice

First you validate object by spring when is create by form, and second time by hibernate before persistence (it's default behavior). As I understood hibernate make validation outside Spring context so Autowired doesn't work. That is why you get NullPointerException.

edited May 23 '17 at 12:24

Community

1
1

answered Jan 21 '17 at 01:23

QuestionMaker

161
7

score 0 · Answer 2 · answered Nov 14 '19 at 14:42

By this line:

it.besmart.validator.UniqueConstraintValidator.getSession(UniqueConstraintValidator.java:27)

it is saying that getSession() throws a NPE. I guess getSession(), if is the line 27, does not find sessionFactory. @Autowired is not working here.

And, I actually doubt the decision of mixing the validator with business logic; the validator should return true when the incoming value is good, and false if is bad; nothing more. You should not make it @Transactional and saving things into DB. No, code smell against SRP.

Hibernate Validation + Custom Constraint + java.lang.NullPointerException

2 Answers2