ClassCastException ParameterizedType

[ysbelman]

I am getting a strange exception when trying to configure annotated JPA transactions. Running in Tomcat, Spring 2.5.4, Hibernate 3.2.5, cglib 2.2

My context:

<tx:annotation-driven transaction-manager="transactionManager"/>

<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
	<property name="entityManagerFactory" ref="entityManagerFactory"/>
	<property name="dataSource" ref="dataSource"/>
</bean>	

<bean id="entityManagerFactory"
	class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
	<property name="persistenceUnitName" value="p1" />
	<property name="dataSource" ref="dataSource" />
	<property name="persistenceXmlLocation" value="classpath:persistence.xml" />
	<property name="jpaVendorAdapter">
		<bean
			class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
			<property name="showSql" value="true" />
			<property name="generateDdl" value="true" />
			<property name="databasePlatform" value="org.hibernate.dialect.MySQLDialect" />
		</bean>
	</property>
</bean>

class that's blowing up on startup:

Transactional
@Repository
public abstract class BaseDao<T extends Serializable, K extends Serializable> {
	@PersistenceContext
	protected EntityManager entityMgr;
	private  Class<T> tClass;

	@SuppressWarnings("unchecked")
	protected BaseDao(){
		this.entityMgr = null;

		log.debug("*** genericSuperclass(): " + getClass().getGenericSuperclass());	
		this.tClass = (Class<T>) ((ParameterizedType) getClass()
                .getGenericSuperclass()).getActualTypeArguments()[0];
	}
}

And the exception:

2008-06-19 23:31:52,484 DEBUG [net.mycompany.dao.BaseDao] - <*** genericSuperclass(): net.mycompany.dao.BaseDao<net.mycompany.pm.Address, java.lang.Long>>
2008-06-19 23:31:52,796 DEBUG [net.mycompany.dao.BaseDao] - <*** genericSuperclass(): class net.mycompany.dao.AddressDAO>
2008-06-19 23:31:52,937 INFO [org.hibernate.impl.SessionFactoryImpl] - <closing>
2008-06-19 23:31:52,953 ERROR [org.springframework.web.context.ContextLoader] - <Context initialization failed>
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'addressDAO' defined in ServletContext resource [/WEB-INF/classes/hibernateSpringContext.xml]: Initialization of bean failed; nested exception is org.springframework.aop.framework.AopConfigException: Could not generate CGLIB subclass of class [class net.mycompany.dao.AddressDAO]: Common causes of this problem include using a final class or a non-visible class; nested exception is net.sf.cglib.core.CodeGenerationException: java.lang.ClassCastException-->java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:478)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBeanFactory.java:409)
	at java.security.AccessController.doPrivileged(Native Method)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:380)
	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:264)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:220)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:261)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:185)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:164)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:429)
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:729)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:381)
	at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:255)
	at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:199)
	at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:45)
	at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:3764)

No idea why the constructor is called twice. If I remove the <tx:annotation-driven/>, spring has no problem loading... but i get no transaction mangement with out it. You can see the debug being called twice, and only when <tx:annotation-driven> is present in config.
I have not found anyone else experiencing the same problem. Any clue as to what it means?

Help, please.

[djreep81]

ysbelman,

I am having the exact same problem. Applying the @Transactional annotation causes the problem. I am using a GenericDAO, same as your BaseDAO. Have you found a solution to this? I can use everything fine, but when I want to apply the transaction annotation it bombs out.


Caused by: org.springframework.aop.framework.AopConfigExcepti on: Could not generate CGLIB subclass of class [class com.retailstore.dao.StoreIPDAO]: Common causes of this problem include using a final class or a non-visible class; nested exception is net.sf.cglib.core.CodeGenerationException: java.lang.ClassCastException-->java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType
at org.springframework.aop.framework.Cglib2AopProxy.g etProxy(Cglib2AopProxy.java:207)
at org.springframework.aop.framework.ProxyFactory.get Proxy(ProxyFactory.java:110)
at org.springframework.aop.framework.autoproxy.Abstra ctAutoProxyCreator.createProxy(AbstractAutoProxyCr eator.java:490)
at org.springframework.aop.framework.autoproxy.Abstra ctAutoProxyCreator.wrapIfNecessary(AbstractAutoPro xyCreator.java:365)
at org.springframework.aop.framework.autoproxy.Abstra ctAutoProxyCreator.postProcessAfterInitialization( AbstractAutoProxyCreator.java:325)
at org.springframework.beans.factory.support.Abstract AutowireCapableBeanFactory.applyBeanPostProcessors AfterInitialization(AbstractAutowireCapableBeanFac tory.java:361)
at org.springframework.beans.factory.support.Abstract AutowireCapableBeanFactory.initializeBean(Abstract AutowireCapableBeanFactory.java:1344)
at org.springframework.beans.factory.support.Abstract AutowireCapableBeanFactory.doCreateBean(AbstractAu towireCapableBeanFactory.java:473)
... 29 more
Caused by: net.sf.cglib.core.CodeGenerationException: java.lang.ClassCastException-->java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType
at net.sf.cglib.core.ReflectUtils.newInstance(Reflect Utils.java:235)
at net.sf.cglib.core.ReflectUtils.newInstance(Reflect Utils.java:220)
at net.sf.cglib.core.ReflectUtils.newInstance(Reflect Utils.java:216)
at net.sf.cglib.proxy.Enhancer.createUsingReflection( Enhancer.java:640)
at net.sf.cglib.proxy.Enhancer.firstInstance(Enhancer .java:538)
at net.sf.cglib.core.AbstractClassGenerator.create(Ab stractClassGenerator.java:225)
at net.sf.cglib.proxy.Enhancer.createHelper(Enhancer. java:377)
at net.sf.cglib.proxy.Enhancer.create(Enhancer.java:2 85)
at org.springframework.aop.framework.Cglib2AopProxy.g etProxy(Cglib2AopProxy.java:201)
... 36 more

Caused by: java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType
at com.retailstore.dao.GenericDAO.<init>(GenericDAO.j ava:21)
at com.retailstore.dao.StoreIPDAO.<init>(StoreIPDAO.j ava:15)
at com.retailstore.dao.StoreIPDAO$$EnhancerByCGLIB$$4 d474fc9.<init>(<generated>)
at sun.reflect.NativeConstructorAccessorImpl.newInsta nce0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInsta nce(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newI nstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Construc tor.java:513)
at net.sf.cglib.core.ReflectUtils.newInstance(Reflect Utils.java:228)


Please let me know what you did... I'm lost here. I guess I will have to keep digging.

[djreep81]

Ok, after doing some research, I have determined that typically, the Transactional annotations belong in the service layer. They should be removed from the DAO layer. Make sure that the service layer implements and interface. I believe that you will need to annotate the method with 'Transactional' and have that method implement the interface in order for it to work.

Thanks,
David

[ysbelman]

exactly. The lack of interfaces affected the proxying. I fixed it this way:

@Transactional
@Repository
public abstract class BaseDao<T extends Serializable, K extends Serializable> implements IBaseDAO<T, K> {
	
	@PersistenceContext
	protected EntityManager entityMgr;
    private  Class<T> tClass;

@Transactional
@Repository
public class AddressDAO  extends BaseDao<Address, Long> implements IAddressDAO {
	protected final static Log log = LogFactory.getLog(AddressDAO.class);

}

public interface IAddressDAO extends IBaseDAO<Address, Long>{
}

public interface IBaseDAO<T extends Serializable, K extends Serializable> {
	
	void create(T entity);
	T retrieve(K key);
	T update(T entity);
	void delete(K key);

}

Spring config

<bean id="addressDao" class="net.company.dao.AddressDAO" />

accessing:

@Autowired
private IAddressDAO addressDAO;

or access yourself via context:

IAddressDAO addressDAO =  (IAddressDAO)ctx.getBean("addressDAO");

This should help.

[thebravedave]

Hi YSbelman, im trying to work this example but im getting an exception:

Exception in thread "main" java.lang.NullPointerException
at data.test.EventDAO.getAll(EventDAO.java:43)
at data.test.EventDAO.getAll(EventDAO.java:1)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Nativ e Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknow n Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Un known Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.aop.support.AopUtils.invokeJoi npointUsingReflection(AopUtils.java:309)
at org.springframework.aop.framework.ReflectiveMethod Invocation.invokeJoinpoint(ReflectiveMethodInvocat ion.java:183)
at org.springframework.aop.framework.ReflectiveMethod Invocation.proceed(ReflectiveMethodInvocation.java :150)
at org.springframework.transaction.interceptor.Transa ctionInterceptor.invoke(TransactionInterceptor.jav a:110)
at org.springframework.aop.framework.ReflectiveMethod Invocation.proceed(ReflectiveMethodInvocation.java :172)
at org.springframework.aop.framework.JdkDynamicAopPro xy.invoke(JdkDynamicAopProxy.java:202)
at $Proxy15.getAll(Unknown Source)
at data.test.Main.main(Main.java:20)

______________________________________________

Here is my Event DAO

public class EventDAO extends BaseDao<Event, Long> implements IEventsDAO{

@Override
public void create(Event entity) {
// TODO Auto-generated method stub

}


@Override
public Event retrieve(Long key) {
// TODO Auto-generated method stub
Query query = entityMgr.createQuery("SELECT * FROM Event WHERE id = 1");
return (Event) query.getResultList();

}


@Override
public Event update(Event entity) {
// TODO Auto-generated method stub
return null;
}

@Override
public void delete(Long key) {
// TODO Auto-generated method stub

}


@Override
public List<Event> getAll(Long key) {
// TODO Auto-generated method stub
Query query = entityMgr.createQuery("SELECT * FROM Events");
return (List<Event>) query.getResultList();
}

}

______________________________________________
I added an additional method getAll().
Im trying to run it through a main method:


public static void main(String[] args) {
// TODO Auto-generated method stub

ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext .xml");
IEventsDAO eventsDAO = (IEventsDAO)ctx.getBean("eventDao");
List<Event> events = (List<Event>) eventsDAO.getAll(new Long(1));
for(Event e: events)
System.out.println(e.getName());
}

[rherrick]

Another thing to try is to modify the setting of the proxy-target-class attribute to the <tx:annotation-driven> element. I got this error after setting it to false:

<tx:annotation-driven proxy-target-class="true" />

I removed that (I was trying to solve another problem by adding it) so that it was:

<tx:annotation-driven />

Note that the default is false for that attribute.

Once I had done that, this error went away (my other error was still there, but as it happens the cause was non-Spring-related, but the problem was just manifesting in the Spring code).
HTH.