I'm using Hibernate 5.1.0.Final with ehcache and Spring 3.2.11.RELEASE. I have the following @Cacheable annotation set up in one of my DAOs:
@Override
@Cacheable(value = "main")
public Item findItemById(String id)
{
return entityManager.find(Item.class, id);
}
The item being returned has a number of assocations, some of which are lazy. So for instance, it (eventually) references the field:
@ManyToMany(fetch = FetchType.LAZY)
@JoinTable(name = "product_category", joinColumns = { @JoinColumn(name = "PRODUCT_ID") }, inverseJoinColumns = { @JoinColumn(name = "CATEGORY_ID") })
private List<Category> categories;
I notice that within one of my methods that I mark as @Transactional, when the above method is retrieved from the second level cache, I get the below exception when trying to iterate over the categories field:
@Transactional(readOnly=true)
public UserContentDto getContent(String itemId, String pageNumber) throws IOException
{
Item Item = contentDao.findItemById(ItemId);
…
// Below line causes a “LazyInitializationException” exception
for (Category category : item.getParent().getProduct().getCategories())
{
The stack trace is:
16:29:42,557 INFO [org.directwebremoting.log.accessLog] (ajp-/127.0.0.1:8009-18) Method execution failed: : org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: org.mainco.subco.ecom.domain.Product.standardCategories, could not initialize proxy - no Session
at org.hibernate.collection.internal.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:579) [hibernate-myproject-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:203) [hibernate-myproject-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:558) [hibernate-myproject-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.collection.internal.AbstractPersistentCollection.read(AbstractPersistentCollection.java:131) [hibernate-myproject-5.1.0.Final.jar:5.1.0.Final]
at org.hibernate.collection.internal.PersistentBag.iterator(PersistentBag.java:277) [hibernate-myproject-5.1.0.Final.jar:5.1.0.Final]
at org.mainco.subco.ebook.service.ContentServiceImpl.getCorrelationsByItem(ContentServiceImpl.java:957) [myproject-90.0.0-SNAPSHOT.jar:]
at org.mainco.subco.ebook.service.ContentServiceImpl.getContent(ContentServiceImpl.java:501) [myproject-90.0.0-SNAPSHOT.jar:]
at sun.reflect.GeneratedMethodAccessor819.invoke(Unknown Source) [:1.6.0_65]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) [rt.jar:1.6.0_65]
at java.lang.reflect.Method.invoke(Method.java:597) [rt.jar:1.6.0_65]
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317) [spring-aop-3.2.11.RELEASE.jar:3.2.11.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183) [spring-aop-3.2.11.RELEASE.jar:3.2.11.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150) [spring-aop-3.2.11.RELEASE.jar:3.2.11.RELEASE]
at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:96) [spring-tx-3.2.11.RELEASE.jar:3.2.11.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:260) [spring-tx-3.2.11.RELEASE.jar:3.2.11.RELEASE]
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:94) [spring-tx-3.2.11.RELEASE.jar:3.2.11.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) [spring-aop-3.2.11.RELEASE.jar:3.2.11.RELEASE]
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:91) [spring-aop-3.2.11.RELEASE.jar:3.2.11.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) [spring-aop-3.2.11.RELEASE.jar:3.2.11.RELEASE]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204) [spring-aop-3.2.11.RELEASE.jar:3.2.11.RELEASE]
at com.sun.proxy.$Proxy126.getContent(Unknown Source)
I understand what the Hibernate session is closed — I do not care about why this happens. Also, it is NOT an option o make the above association eager (instead of lazy). Given that, how can I solve this problem?
Edit: Here is how my ehccahe.xml is configured …
<ehcache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../config/ehcache.xsd" updateCheck="false">
<!-- This is a default configuration for 256Mb of cached data using the JVM's heap, but it must be adjusted
according to specific requirement and heap sizes -->
<defaultCache maxElementsInMemory="10000"
eternal="false"
timeToIdleSeconds="86400"
timeToLiveSeconds="86400"
overflowToDisk="false"
memoryStoreEvictionPolicy="LRU">
</defaultCache>
<cache name="main" maxElementsInMemory="10000" />
<cacheManagerPeerProviderFactory
class="net.sf.ehcache.distribution.RMICacheManagerPeerProviderFactory"
properties="peerDiscovery=automatic, multicastGroupAddress=230.0.0.1,
multicastGroupPort=4446, timeToLive=32"/>
<cacheManagerPeerListenerFactory
class="net.sf.ehcache.distribution.RMICacheManagerPeerListenerFactory"
properties="hostName=localhost, port=40001,
socketTimeoutMillis=2000"/>
</ehcache>
and here is how I’m plugging it into my Spring context …
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="packagesToScan" value="org.mainco.subco" />
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"/>
</property>
<property name="dataSource" ref="dataSource"/>
<property name="jpaPropertyMap" ref="jpaPropertyMap" />
</bean>
<cache:annotation-driven key-generator="cacheKeyGenerator" />
<bean id="cacheKeyGenerator" class="org.mainco.subco.myproject.util.CacheKeyGenerator" />
<bean id="cacheManager"
class="org.springframework.cache.ehcache.EhCacheCacheManager"
p:cacheManager-ref="ehcache"/>
<bean id="ehcache" class="org.springframework.cache.ehcache.EhCacheManagerFactoryBean"
p:configLocation="classpath:ehcache.xml"
p:shared="true" />
<util:map id="jpaPropertyMap">
<entry key="hibernate.show_sql" value="false" />
<entry key="hibernate.hbm2ddl.auto" value="validate"/>
<entry key="hibernate.dialect" value="org.hibernate.dialect.MySQL5InnoDBDialect"/>
<entry key="hibernate.transaction.manager_lookup_class" value="org.hibernate.transaction.JBossTransactionManagerLookup" />
<entry key="hibernate.cache.region.factory_class" value="org.hibernate.cache.ehcache.EhCacheRegionFactory"/>
<entry key="hibernate.cache.provider_class" value="org.hibernate.cache.EhCacheProvider"/>
<entry key="hibernate.cache.use_second_level_cache" value="true" />
<entry key="hibernate.cache.use_query_cache" value="false" />
<entry key="hibernate.generate_statistics" value="false" />
</util:map>
<bean id="entityManager" class="org.springframework.orm.jpa.support.SharedEntityManagerBean">
<property name="entityManagerFactory" ref="entityManagerFactory"/>
</bean>