Use of @OneToMany or @ManyToMany targeting an unmapped class error from EmbeddedID

Question

I am using spring boot with JPA for a simple CRUD application.
I have an object (ObjectD) with an embedded ID (PrimaryKey), which has a composite primary key referencing the id's of two base objects (ObjectA and ObjectB) via a one-to-many relationship.
However, I am getting an error saying

org.hibernate.AnnotationException: Use of @OneToMany or @ManyToMany targeting an unmapped class: ObjectA.primarykeys[PrimaryKey].

This seems to be a fairly common problem, but I have tried all the suggestions in all the responses and can't seem to break through. Assistance would be highly appreciated.

I have read through all similar questions and tried all the suggestions, including:

• made sure the annotation is javax.persistence.Entity, and not org.hibernate.annotations.Entity

• changing the mappedBy field on the OneToMany sides to PrimaryKey.objecta or PrimaryKey.objectb respectively

• I am using Spring boot so I don't have a hibernate.cfg or persistence config file. I am relying on spring boot jpa to do the necessary.

The only way I can start the ApplicationContext is to remove the OneToMany fields on ObjectA and B respectively. But then I don't have a reference to the PrimaryKey from ObjectA and ObjectB which I need. I know the problem relates to the OneToMany relationship, but I don't know how to solve it.

This is a diagram of what I am trying to do in the database: The PrimaryKey class is intended to deal with the composite primary key in ObjectD. This is what I am trying to do with my class mappings to achieve the desired outcome:

@Entity
public class ObjectA {
    @Id @GeneratedValue(strategy = GenerationType.AUTO) @Column(nullable = false) private Long objectAId;

    @OneToMany(mappedBy = "objecta", cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.EAGER)
    private Set<PrimaryKey> primarykeys = new HashSet<PrimaryKey>();

    @Column(nullable = false, unique = true, length = 200) private String name;

//constructor, getters, setters, equals and hashcode left out for brevity
}   

@Entity
public class ObjectB {
    @Id @GeneratedValue(strategy = GenerationType.AUTO) @Column(nullable = false) private Long objectBId;
    @Column(nullable = false, unique = true, length = 200) private String name;
    @OneToMany(mappedBy = "objectb", cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.EAGER) 
    private Set<PrimaryKey> primaryKeys = new HashSet<PrimaryKey>();

//constructor, getters, setters, equals and hashcode left out for brevity   
}

@Embeddable
public class PrimaryKey implements Serializable {
    private static final long serialVersionUID = 1L;

    @ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)  
    @JoinColumn(name="objectAId") 
    private ObjectA objectA;
    @ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL) 
    @JoinColumn(name="objectBId") 
    private ObjectB objectB;

//constructor, getters, setters, equals and hashcode left out for brevity
}

@Entity
public class ObjectD {
    @EmbeddedId private PrimaryKey primaryKey;
    @Column(nullable = false, unique = true, length = 200) private String name;

//constructor, getters, setters, equals and hashcode left out for brevity
}

I have pasted the stacktrace below.

2019-10-15 11:39:06,203 ERROR [main] org.springframework.boot.SpringApplication: Application run failed org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is org.hibernate.AnnotationException: Use of @OneToMany or @ManyToMany targeting an unmapped class: ObjectA.primarykeys[PrimaryKey] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1694) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:573) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:495) at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1087) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:857) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:548) at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:754) at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:386) at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:127) at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:99) at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:117) at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:108) at org.springframework.test.context.web.ServletTestExecutionListener.setUpRequestContextIfNecessary(ServletTestExecutionListener.java:190) at org.springframework.test.context.web.ServletTestExecutionListener.prepareTestInstance(ServletTestExecutionListener.java:132) at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:246) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:227) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:289) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:291) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:246) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:89) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:41) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:541) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:763) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:463) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:209) Caused by: org.hibernate.AnnotationException: Use of @OneToMany or @ManyToMany targeting an unmapped class: ObjectA.primarykeys[PrimaryKey] at org.hibernate.cfg.annotations.CollectionBinder.bindManyToManySecondPass(CollectionBinder.java:1253) at org.hibernate.cfg.annotations.CollectionBinder.bindStarToManySecondPass(CollectionBinder.java:810) at org.hibernate.cfg.annotations.CollectionBinder$1.secondPass(CollectionBinder.java:735) at org.hibernate.cfg.CollectionSecondPass.doSecondPass(CollectionSecondPass.java:54) at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1640) at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1608) at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:278) at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:861) at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:888) at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:57) at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:390) at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:377) at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1753) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1690) ... 40 common frames omitted 2019-10-15 11:39:06,204 ERROR [main] org.springframework.test.context.TestContextManager: Caught exception while allowing TestExecutionListener [org.springframework.test.context.web.ServletTestExecutionListener@7193666c] to prepare test instance [hysan.test.integrationtests.demo.service.DIntegrationTest@2bb41f5c] java.lang.IllegalStateException: Failed to load ApplicationContext at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:125) at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:108) at org.springframework.test.context.web.ServletTestExecutionListener.setUpRequestContextIfNecessary(ServletTestExecutionListener.java:190) at org.springframework.test.context.web.ServletTestExecutionListener.prepareTestInstance(ServletTestExecutionListener.java:132) at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:246) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:227) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:289) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:291) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:246) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:89) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:41) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:541) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:763) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:463) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:209)

Answer 1

@OneToMany cannot be applied to @Embeddable, only to @Entity.

In other words you cannot write this:

@OneToMany(mappedBy = "objecta", cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.EAGER)
private Set<PrimaryKey> primarykeys = new HashSet<PrimaryKey>();

If it's embeddable - embed it!