Why my hibernate relation doesn't work?

Question

See my class with relation :

@Entity
@Table(name = "t_aquarium")
public class UserPoissonDO {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id")
    private Integer id;
    @ManyToOne(cascade = { CascadeType.PERSIST, CascadeType.MERGE, CascadeType.REFRESH })
    private User user;
    @ManyToOne(cascade = { CascadeType.PERSIST, CascadeType.MERGE, CascadeType.REFRESH })
    private PoissonDO poissonDO;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    public PoissonDO getPoissonDO() {
        return poissonDO;
    }

    public void setPoissonDO(PoissonDO poissonDO) {
        this.poissonDO = poissonDO;
    }
}

When I save it in my BDD with JPA, I've the following error :

 detached entity passed to persist: com.javaquarium.beans.data.PoissonDO; 
 nested exception is org.hibernate.PersistentObjectException: detached entity
 passed to persist: com.javaquarium.beans.data.PoissonDO

In my database, I like to save the UserPoissonDO object with relation to the User and the specie of the Fish.

UserPoisson is associated with one User and one User can have more than one fish.

I think my relation is bad... if it's the case explain me why. I've follow an example for this.

EDIT : See my PoissonUserService for persisting UserPoissonDO

@Service
public class PoissonUserService implements IPoissonUserService {
private final Logger logger = LoggerFactory.getLogger(this.getClass());
private UserRepository userRepository;
private PoissonUserRepository poissonUserRepository;

public PoissonUserService(PoissonUserRepository poissonUserRepository,UserRepository userRepository) {
    this.poissonUserRepository = poissonUserRepository;
    this.userRepository = userRepository;
}

@Override
public List<UserPoissonDO> getUserPoissons(String username) {
    logger.warn("Pram USER : " + userRepository.getClass().getSimpleName());
    User user = userRepository.findByusername(username);
    logger.warn("USER : " + user.getUsername());
    List<UserPoissonDO> lstUserPoissons = new ArrayList<>();
    lstUserPoissons = poissonUserRepository.findByUser(user);
    return lstUserPoissons;
}

@Override
public void save(UserPoissonDO userPoissonDO) {
    poissonUserRepository.save(userPoissonDO);
}

@Override
public void save(List<UserPoissonDO> userPoissonDOList) {
    poissonUserRepository.save(userPoissonDOList);
}

@Override
public void deleteUserPoisson(List<UserPoissonDO> userPoissonDOList) {
    poissonUserRepository.delete(userPoissonDOList);
}

@Override
public void deleteUserPoisson(UserPoissonDO userPoissonDO) {
    poissonUserRepository.delete(userPoissonDO);
}
}

Controller for save UserPoissonDO :
@Controller
public class SaveAquariumAction {

@Autowired
private PoissonUserRepository poissonUserRepository;
@Autowired private UserRepository userRepository;
private IPoissonService poissonService;
private IPoissonUserService poissonUserService;
private final Logger logger = LoggerFactory.getLogger(this.getClass());
private List<UserPoissonDO> userPoissonDOS;
private UserDetails userDetails;

@RequestMapping("/SaveAquarium")
public String listerEspeces(Model model, HttpSession session) {
    userPoissonDOS = (ArrayList)session.getAttribute("userPoissonDOS");
    poissonUserService = new PoissonUserService(poissonUserRepository,userRepository);
    logger.warn("SAVE : " + userPoissonDOS.get(0).getPoissonDO().getId() + " USER ID " + userPoissonDOS.get(0).getUser().getId());
    poissonUserService.save(userPoissonDOS);
    return "redirect:/listerEspeces";
}
}

StackTrace :

org.hibernate.PersistentObjectException: detached entity passed to persist: com.javaquarium.beans.data.PoissonDO
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:124) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:765) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:758) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.jpa.event.internal.core.JpaPersistEventListener$1.cascade(JpaPersistEventListener.java:80) ~[hibernate-entitymanager-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.engine.internal.Cascade.cascadeToOne(Cascade.java:398) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:323) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:162) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:111) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.event.internal.AbstractSaveEventListener.cascadeBeforeSave(AbstractSaveEventListener.java:425) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:249) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:178) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:109) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.jpa.event.internal.core.JpaPersistEventListener.saveWithGeneratedId(JpaPersistEventListener.java:67) ~[hibernate-entitymanager-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:189) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:132) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:58) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:775) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:748) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:753) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:1146) ~[hibernate-entitymanager-5.0.11.Final.jar:5.0.11.Final]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_45]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_45]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_45]
at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_45]
at org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerInvocationHandler.invoke(ExtendedEntityManagerCreator.java:347) ~[spring-orm-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at com.sun.proxy.$Proxy87.persist(Unknown Source) ~[na:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_45]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_45]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_45]
at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_45]
at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:298) ~[spring-orm-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at com.sun.proxy.$Proxy87.persist(Unknown Source) ~[na:na]
at org.springframework.data.jpa.repository.support.SimpleJpaRepository.save(SimpleJpaRepository.java:508) ~[spring-data-jpa-1.11.0.RELEASE.jar:na]
at org.springframework.data.jpa.repository.support.SimpleJpaRepository.save(SimpleJpaRepository.java:542) ~[spring-data-jpa-1.11.0.RELEASE.jar:na]
at org.springframework.data.jpa.repository.support.SimpleJpaRepository.save(SimpleJpaRepository.java:74) ~[spring-data-jpa-1.11.0.RELEASE.jar:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_45]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_45]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_45]
at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_45]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.executeMethodOn(RepositoryFactorySupport.java:504) ~[spring-data-commons-1.13.0.RELEASE.jar:na]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:489) ~[spring-data-commons-1.13.0.RELEASE.jar:na]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:461) ~[spring-data-commons-1.13.0.RELEASE.jar:na]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:61) ~[spring-data-commons-1.13.0.RELEASE.jar:na]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99) ~[spring-tx-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:282) ~[spring-tx-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96) ~[spring-tx-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136) ~[spring-tx-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:133) ~[spring-data-jpa-1.11.0.RELEASE.jar:na]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) ~[spring-aop-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:57) ~[spring-data-commons-1.13.0.RELEASE.jar:na]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213) ~[spring-aop-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at com.sun.proxy.$Proxy95.save(Unknown Source) ~[na:na]
at com.javaquarium.business.PoissonUserService.save(PoissonUserService.java:46) ~[classes/:na]
at com.javaquarium.action.SaveAquariumAction.listerEspeces(SaveAquariumAction.java:44) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_45]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_45]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_45]
at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_45]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:317) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:127) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:91) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:114) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:137) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:170) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:200) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:116) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.csrf.CsrfFilter.doFilterInternal(CsrfFilter.java:100) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:64) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:214) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:177) ~[spring-security-web-4.2.1.RELEASE.jar:4.2.1.RELEASE]
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:262) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) ~[tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:474) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:783) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:798) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1434) [tomcat-embed-core-8.5.11.jar:8.5.11]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.11.jar:8.5.11]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_45]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_45]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.11.jar:8.5.11]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_45]

Did you set the `id` field before you tried to save it? Don't, otherwise JPA will think you want to update an existing entity instead of insert a new entity. — Jesper, Feb 22 '17 at 15:35
You talk about ID in UserPoissonDO or in my PoissonDO and User object ? My ID are set correctly in my Object User and PoissonDO but there is no ID in my UserPoissonDO. — QuentinV, Feb 22 '17 at 15:39
Your relationship mappings look fine. Please provide a small example of how you are persisting your UserPoissonDO entities. I suspect there is an issue there. — Will Dazey, Feb 22 '17 at 15:48
@QuentinV Ok, getting warmer. PoissonUserService is not what I am looking for tho. Do you perhaps have a test class that calls this service? Perhaps it may be more informative if you provided the exception stack trace. — Will Dazey, Feb 22 '17 at 16:15
I've added the stacktrace + The Controller who call the service — QuentinV, Feb 22 '17 at 16:20
For `com.javaquarium.beans.data.PoissonDO` to be detached, it means the PoissonDO object is no longer being managed by a persistence context. There are many reasons this could be. For instance, perhaps the EntityManager it was obtained from was closed or there was a transaction rollback. — Will Dazey, Feb 22 '17 at 16:24
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/136379/discussion-between-will-dazey-and-quentinv). — Will Dazey, Feb 22 '17 at 16:31

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

I believe the solution provided here: Spring data jpa detached entity, will also work for this situation.

The issue is that UserPoissonDO is a new object, but its PoissonDO is detached. Spring will attempt to persist UserPoissonDO since it is a new object, but doesn't know that it needs to merge() PoissonDO into the existing persistence context and manage it.

As explained in the linked post:

If you can ensure that PoissonDO will be saved separately or already exists, removing CascadeType.PERSIST will work. Otherwise, you will need to perform a merge() using a custom repository and EntityManager.

In my case, remove CascadeType.PERSIST work after rebuild the table. — QuentinV, Feb 22 '17 at 18:55

Why my hibernate relation doesn't work?

1 Answers1