Java Hibernate LazyInitializationException only when running with JUnit only

Question

I am using Java + Spring boot(Ver 2.1.16) + Hibernate + JPA for an API project. I have several models with several OneToMany relationships. I haven't mentioned a fetch type but as I know it's Eager in default according to my used Hibernate version. I have mentioned @Transactional in my service method also. All good when I get data calling to the API endpoint via Postman (I receive all fields including OneToMany) without any exception. But when I call the service method via Unit tests, I get following exception.

org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.ccc.common.model.InstantiatedVnfInfo.vnfcInfo, could not initialize proxy - no Session

at org.hibernate.collection.internal.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:602)
at org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:217)
at org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:581)
at org.hibernate.collection.internal.AbstractPersistentCollection.read(AbstractPersistentCollection.java:148)
at org.hibernate.collection.internal.PersistentBag.toString(PersistentBag.java:624)
at java.base/java.lang.String.valueOf(String.java:3367)
at java.base/java.lang.StringBuilder.append(StringBuilder.java:167)
at org.junit.Assert.failNotNull(Assert.java:755)
at org.junit.Assert.assertNull(Assert.java:737)
at org.junit.Assert.assertNull(Assert.java:747)
at hms.vnfm.lcm.service.VnfInstancesServiceTest.testCreateVnfInstanceWithNullFields(VnfInstancesServiceTest.java:75)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate(RunBeforeTestExecutionCallbacks.java:74)
at org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate(RunAfterTestExecutionCallbacks.java:84)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:251)
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$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:220)
at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:53)

What can be the issue?

Duy Nguyen · Accepted Answer · 2021-01-25 03:26:05Z

3

When you call the rest API using postman, it works because Spring Boot offers a feature called OpenSessionInViewFilter which open a hibernate session for the current session of your HTTP request. When you call the service method directly by the test method without being annotated by @Transactional, the lazy fetching does not work because there is no hibernate session opened.

answered Jan 25, 2021 at 3:26

Duy Nguyen

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Udara Seneviratne · Accepted Answer · 2021-01-25 02:42:05Z

0

I could resolve the issue after adding

@Transactional

to my Test methods also

answered Jan 25, 2021 at 2:42

Udara Seneviratne

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