Getting LazyInitializationException on JUnit Test Case

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Problem running JUnit Test inside a Spring MVC Application. Test 1 (insertTweet) seems to run fine, however on Test 2 I get an "LazyInitializationException" Exception (see full stactrace below). I understand why it is thrown but not sure why the session is closing and how to reopen it at the begining of every test 2 (or keep the existing session open for the remaining tests to complete)? I have pasted the entire StackTrace thrown along with Test Classes.

org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.project.user.User.tweets, could not initialize proxy - no Session
    at org.hibernate.collection.internal.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:566)
    at org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:186)
    at org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:545)
    at org.hibernate.collection.internal.AbstractPersistentCollection.write(AbstractPersistentCollection.java:370)
    at org.hibernate.collection.internal.PersistentBag.add(PersistentBag.java:291)
    at com.project.core.tweet.Tweet.<init>(Tweet.java:113)
    at com.project.core.service.impl.FanoutServiceTester.insertTweet(FanoutServiceTester.java:69)
    at com.project.core.service.impl.FanoutServiceTester.testInsertRetweet(FanoutServiceTester.java:62)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
    at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:88)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

@RunWith(SpringJUnit4ClassRunner.class)
@TestExecutionListeners({ServiceTestExecutionListener.class})
@ActiveProfiles("test")
public abstract class AbstractServiceImplTest extends AbstractTransactionalJUnit4SpringContextTests {

    @PersistenceContext
    protected EntityManager em;

    @Autowired protected TweetService tweetService;
    @Autowired protected UserService userService;

}


public class FanoutServiceTester extends AbstractServiceImplTest{
    private static User user = null;
    private static User userTwo = null;



    @Before
    public void setUp() throws Exception {

        user = userService.findByUserId(1);


        //UserTwo Follows User One
        userTwo  = userService.findByUserId(2);



    }


    @Test
    public final void testInsertTweet() {       
        insertTweet();

        //Assert Here

    }



    @Test
    public final void testInsertRetweet() {
        insertTweet();
        //Assert Here

    }


    private Tweet insertTweet(){
        Tweet tweet = new Tweet(user);
        String text = "This is a Message";  
        tweet.setTweetText(text);
        Tweet saved = tweetService.save(tweet);
        return saved;
    }

}

Delogu answered 6/11, 2013 at 13:34 Comment(1)

What do you expect us to do with what you've shown? Post your config and your test. – Candiscandle 6/11, 2013 at 13:45

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I've run into this and the error is a bit misleading. The Session is not being closed.

When you call userService.findByUserId(1); it probably does a Join to a Tweets table and so you get this collection back:

com.project.user.User.tweets

Hibernate does not initialize this collection by default. To initialize it, you can call Hibernate.initialize() for example, like this:

Hibernate.initialize(user.getTweets());

Of course substitute getTweets() for the actual method that returns the tweets collection.

Magill answered 6/11, 2013 at 21:39 Comment(9)

That seems to work. However I'm working with JPA 2 and having "Hibernate.initialize()" inside a JPA Entity Class seems odd. Could it be that junit is calling hibernate instead of jpa? – Delogu 7/11, 2013 at 14:7

Yes that would be odd :-) Then the Tweets collection in the entity needs to be fetched eagerly (it will be lazy, i.e. retrieved but not initialized, by default). Try annotating with @OneToMany(fetch=FetchType.EAGER) – Magill 7/11, 2013 at 14:37

I'm not sure what you mean? Unless I'm missing something, If I explicitly define it to "Eagerly" Load the Collection, I expect it to do just that. Besides, I'd like to exhaust all other options first. – Delogu 7/11, 2013 at 14:54

What's wrong with eagerly loading the collection in this case? – Magill 7/11, 2013 at 14:58

Tweets Collection may contain a lot of records. If I was to "Eagerly" Load this Collection then every time I load the "User" Object, it will also load the Tweets Collection, which can lead to performance issues. – Delogu 7/11, 2013 at 15:8

You are still using Hibernate in the project, right? Since Hibernate falls back on JPA where JPA can do the job, i.e. JPA Entities, I think it would still be ok to initialize the collection with Hibernate.initialize() right before you need to access it in your test case. I don't think JPA has an initialize collection method. – Magill 7/11, 2013 at 15:17

Aren't you accessing the tweets somewhere in your code? i.e. when you retriever the user, user.getTweets().get(0) or something along those lines? – Magill 7/11, 2013 at 15:55

I added the line in method @Before which seems to work. I wonder, if this Exception is thrown when running the actual application on server. – Delogu 7/11, 2013 at 15:59

I would expect it whenever a lazily fetched collection is accessed before being initialized, just take care to initialize it before using it and it will not throw the exception on the server – Magill 7/11, 2013 at 17:3

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89

add the @Transactional on your test methods – ben75 Nov 6 '13 at 14:29

Yeah, I have solved the problem:

        @RunWith(SpringJUnit4ClassRunner.class)
        @ContextConfiguration(locations = { "classpath*:applicationContext.xml"})
        @Transactional
        public class UserinfoActionTest extends StrutsSpringJUnit4TestCase<UserinfoAction> {
                @Test
            public void testLogin2(){
                          request.setParameter("jsonQueryParam", param);
                String str = null;
        try {

                    str = executeAction("/login.action");
                    HashMap<String,List<TUserinfo>> map = (HashMap<String,List<TUserinfo>>)findValueAfterExecute("outDataMap"); }
 catch (Exception e) {
                    e.printStackTrace();
                }

            }


        @Controller
        @Results({  
            @Result(name="json",type="json"
                    , params={"root","outDataMap","excludeNullProperties","true"
                            ,"excludeProperties","^ret\\[\\d+\\]\\.city\\.province,^ret\\[\\d+\\]\\.enterprise\\.userinfos","enableGZIP","true"
                    })
        })
        public class UserinfoAction extends BaseAction {
                    @Action(value="login")

            public String login(){
                if(jsonQueryParam!=null && jsonQueryParam.length()>0)
                {
                    user = JsonMapper.fromJson(jsonQueryParam, TUserinfo.class);
                }
                Assert.notNull(user);
                 //RESULT="ret" addOutJsonData: put List<TUserinfo> into outDataMap with key RESULT for struts2 JSONResult  
                addOutJsonData(RESULT, service.login(user));
                return JSON;
            }

Prindle answered 8/1, 2014 at 2:10 Comment(2)

Interesting discussion of transactional: marcobehler.com/2014/06/25/should-my-tests-be-transactional – Oppress 20/5, 2020 at 13:49

Having @Transactional in integration test is a nightmare, which can lead to wrongly evaluated tests. Just avoid it and do your test as it should be. kode-krunch.com/2021/07/hibernate-traps-transactional.html – Paleoecology 22/11, 2022 at 11:35

B

14

You are missing the TransactionalTestExecutionListener. It is required and present by default when you don't define any TestExecutionListener yourself. But as soon as you define one explicitely : it is removed.

So declare it :

@TestExecutionListeners({ServiceTestExecutionListener.class, TransactionalTestExecutionListener.class})

See "Testing - Transaction management" of the 3.2.x Spring docs.

Barret answered 6/11, 2013 at 13:56 Comment(4)

I made the changes as suggested but I am still getting the mentioned exception. – Delogu 6/11, 2013 at 14:13

add the @Transactional on your test methods – Barret 6/11, 2013 at 14:29

I added that too. I think all that is not necessary if you're extending AbstractTransactionalJUnit4SpringContextTests Class, which I am doing. – Delogu 6/11, 2013 at 14:32

I got the same issue fixed in JUnit test case by just adding TransactionalTestExecutionListener to the listeners. Thanks. :) – Tuff 12/2, 2016 at 14:26

L

12

Enjoy

@RunWith(SpringRunner.class)
@SpringBootTest
@Transactional // The magic is here
public class YourClassTests {

...

}

Lysozyme answered 11/11, 2019 at 16:39 Comment(1)

No, please no. I am finding this in projects, that are done by try-and-let-see-what-it-does developers. – Paleoecology 22/11, 2022 at 11:37

M

7

I've run into this and the error is a bit misleading. The Session is not being closed.

When you call userService.findByUserId(1); it probably does a Join to a Tweets table and so you get this collection back:

com.project.user.User.tweets

Hibernate does not initialize this collection by default. To initialize it, you can call Hibernate.initialize() for example, like this:

Hibernate.initialize(user.getTweets());