| For a bidirectional @OneToOne associations mapped as follows:
@Entity
public class Phone {
@Id
@GeneratedValue
private Long id;
private String number;
@OneToOne(mappedBy = "phone", cascade = CascadeType.ALL, orphanRemoval = true)
private PhoneDetails details;
public Phone() {}
public Phone(String number) {
this.number = number;
}
public Long getId() {
return id;
}
public String getNumber() {
return number;
}
public PhoneDetails getDetails() {
return details;
}
public void addDetails(PhoneDetails details) {
details.setPhone(this);
this.details = details;
}
public void removeDetails() {
if (details != null) {
details.setPhone(null);
this.details = null;
}
}
}
@Entity
public class PhoneDetails {
@Id
@GeneratedValue
private Long id;
private String provider;
private String technology;
@OneToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "phone_id")
private Phone phone;
public PhoneDetails() {}
public PhoneDetails(String provider, String technology) {
this.provider = provider;
this.technology = technology;
}
public String getProvider() {
return provider;
}
public String getTechnology() {
return technology;
}
public void setTechnology(String technology) {
this.technology = technology;
}
public Phone getPhone() {
return phone;
}
public void setPhone(Phone phone) {
this.phone = phone;
}
}
If the application developer wants to assign two children for the same parent:
doInJPA(entityManager -> {
Phone phone = new Phone("123-456-7890");
PhoneDetails details = new PhoneDetails("T-Mobile", "GSM");
phone.addDetails(details);
entityManager.persist(phone);
PhoneDetails otherDetails = new PhoneDetails("T-Mobile", "CDMA");
otherDetails.setPhone(phone);
entityManager.persist(otherDetails);
entityManager.flush();
entityManager.clear();
phone = entityManager.find(Phone.class, phone.getId());
phone.getDetails().getProvider();
});
There's no exception being thrown when fetching the parent-side Phone, which has two PhoenDetails. This happens when using the default EAGER fetching, which relies on a LEFT JOIN to grab the parent and the child in the same query. If the fetch strategy is changes to LAZY:
@OneToOne(mappedBy = "phone", cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.LAZY)
private PhoneDetails details;
When rerunning the same logic, an exception is being thrown this time:
javax.persistence.PersistenceException: org.hibernate.HibernateException: More than one row with the given identifier was found: 1, for class: com.vladmihalcea.guide.association.BidirectionalOneToOneTest$PhoneDetails
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1692)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1619)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.find(AbstractEntityManagerImpl.java:1106)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.find(AbstractEntityManagerImpl.java:1033)
at com.vladmihalcea.guide.association.BidirectionalOneToOneTest.lambda$testConstraint$1(BidirectionalOneToOneTest.java:49)
at com.vladmihalcea.guide.association.BidirectionalOneToOneTest$$Lambda$20/1911978617.accept(Unknown Source)
at com.vladmihalcea.book.hpjp.util.AbstractTest.doInJPA(AbstractTest.java:880)
at com.vladmihalcea.guide.association.BidirectionalOneToOneTest.testConstraint(BidirectionalOneToOneTest.java:36)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
at org.junit.runner.JUnitCore.run(JUnitCore.java:160)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:234)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:74)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
Caused by: org.hibernate.HibernateException: More than one row with the given identifier was found: 1, for class: com.vladmihalcea.guide.association.BidirectionalOneToOneTest$PhoneDetails
at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:86)
at org.hibernate.loader.entity.EntityLoader.loadByUniqueKey(EntityLoader.java:143)
at org.hibernate.persister.entity.AbstractEntityPersister.loadByUniqueKey(AbstractEntityPersister.java:2111)
at org.hibernate.type.EntityType.loadByUniqueKey(EntityType.java:685)
at org.hibernate.type.EntityType.resolve(EntityType.java:427)
at org.hibernate.engine.internal.TwoPhaseLoad.doInitializeEntity(TwoPhaseLoad.java:154)
at org.hibernate.engine.internal.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:128)
at org.hibernate.loader.plan.exec.process.internal.AbstractRowReader.performTwoPhaseLoad(AbstractRowReader.java:238)
at org.hibernate.loader.plan.exec.process.internal.AbstractRowReader.finishUp(AbstractRowReader.java:209)
at org.hibernate.loader.plan.exec.process.internal.ResultSetProcessorImpl.extractResults(ResultSetProcessorImpl.java:123)
at org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:122)
at org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:86)
at org.hibernate.loader.entity.plan.AbstractLoadPlanBasedEntityLoader.load(AbstractLoadPlanBasedEntityLoader.java:167)
at org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:3955)
at org.hibernate.event.internal.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:508)
at org.hibernate.event.internal.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:478)
at org.hibernate.event.internal.DefaultLoadEventListener.load(DefaultLoadEventListener.java:219)
at org.hibernate.event.internal.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:278)
at org.hibernate.event.internal.DefaultLoadEventListener.doOnLoad(DefaultLoadEventListener.java:121)
at org.hibernate.event.internal.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:89)
at org.hibernate.internal.SessionImpl.fireLoad(SessionImpl.java:1129)
at org.hibernate.internal.SessionImpl.access$2600(SessionImpl.java:164)
at org.hibernate.internal.SessionImpl$IdentifierLoadAccessImpl.load(SessionImpl.java:2696)
at org.hibernate.internal.SessionImpl.get(SessionImpl.java:975)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.find(AbstractEntityManagerImpl.java:1075)
... 33 more
Test case will be added after knowing the Jira issue number. |