4 Replies Latest reply on Apr 26, 2007 6:05 AM by wolfc

EntityManager Null when trying to inject into stateless sess

bmant Apr 25, 2007 8:41 AM

Hi,

I'm having an issue deploying to JBoss 4.0.5-ejb3. When I try to inject my EntityManager in my code:

@PersistenceContext EntityManager em;

it is always null. However, if I do:

 EntityManagerFactory emf = Persistence.createEntityManagerFactory("myDS");
em = emf.createEntityManager();

This is my setup:

I have a java web service that calls my Stateless Session bean. In my session bean, I try to inject the PersistenceContext, so I can utilize my Entity Beans.

I have a .ear archive that I deploy to the server/default/deploy directory (using JBuilder 2007) - with a .war (that contains my web service) and a .jar that contains my beans (entity and session).

I have everything annotated according to the documentation. All of the documentation says that it should work.
ISampleClass is the @Local Interface class.

@Stateless (name="SampleClass")
public class SampleClass implements ISampleClass

 @PersistenceContext (unitName="myDS")
 EntityManager em;

 public Resource findResource() {
 Resource resource = em.find(Resource.class, 1);
 return resource;
 }
}

I've also tried:

@TransactionAttribute (TransactionAttributeType.REQUIRED)

at the class and method level.

I wrote a client that calls the web service (Axis 1.3 client generated). It calls the service fine, but I get a NullPointerException when it tries to call the em.persist() method inside my stateless session bean.

Here is my persistence.xml file:

><persistence-unit name="myDS">
 <provider>org.hibernate.ejb.HibernatePersistence</provider>
 <jta-data-source>java:/myDS</jta-data-source>
 <properties>
 <property name="hibernate.hbm2ddl.auto" value="validate"></property>
 <property name="hibernate.dialect"
 value="org.hibernate.dialect.MySQLInnoDBDialect" />
 <property name="hibernate.session_factory_name"
 value="java:hibernate/HibernateFactory" />
 <property name="transaction.factory_class"
 value="org.hibernate.transaction.JTATransactionFactory" />
 <property name="hibernate.cache.use_second_level_cache"
 value="false" />
 <property name="hibernate.transaction.manager_lookup_class"
 value="org.hibernate.transaction.JBossTransactionManagerLookup" />
 </properties>
 </persistence-unit>

I've also tried explicity setting the transaction-type to "JTA" at the persistence-unit level, not setting the provider and leaving the properties section empty.

Here is my mysql-ds.xml file:

<datasources>
 <local-tx-datasource>
 <jndi-name>myDS</jndi-name>
 <connection-url>jdbc:mysql://localhost:3306/myDB</connection-url>
 <driver-class>com.mysql.jdbc.Driver</driver-class>
 <user-name>myuser</user-name>
 <password>mypass</password>
 <connection-property name="socketFactory">com.mysql.jdbc.NamedPipeSocketFactory</connection-property>
 <exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLExceptionSorter</exception-sorter-class-name>
 <metadata>
 <type-mapping>mySQL</type-mapping>
 </metadata>
 </local-tx-datasource>
</datasources

And looking at the JBoss logs with debug on I see this (which seems to me that it's loading correctly):

2007-04-24 09:00:51,656 DEBUG [org.jboss.system.ServiceController] starting service jboss.j2ee:service=EJB3,module=MyApp.jar
2007-04-24 09:00:51,656 DEBUG [org.jboss.ejb3.Ejb3Module] Starting jboss.j2ee:service=EJB3,module=MyApp.jar
2007-04-24 09:00:51,656 DEBUG [org.jboss.ejb3.JmxKernelAbstraction] creating wrapper delegate for: org.jboss.ejb3.entity.PersistenceUnitDeployment
2007-04-24 09:00:51,656 INFO [org.jboss.ejb3.JmxKernelAbstraction] installing MBean: persistence.units:ear=MyEar.ear,jar=MyApp.jar,unitName=myDS with dependencies
2007-04-24 09:00:51,656 INFO [org.jboss.ejb3.JmxKernelAbstraction] jboss.jca:name=pmacDS,service=DataSourceBinding
2007-04-24 09:00:51,656 DEBUG [org.jboss.system.ServiceController] Creating service persistence.units:ear=MyEar.ear,jar=MyApp.jar,unitName=myDS
2007-04-24 09:00:51,656 DEBUG [org.jboss.system.ServiceController] adding depends in ServiceController.register: [jboss.jca:name=myDS,service=DataSourceBinding]
2007-04-24 09:00:51,656 DEBUG [org.jboss.system.ServiceController] recording that persistence.units:ear=MyEar.ear,jar=MyApp.jar,unitName=myDS depends on jboss.jca:name=pmacDS,service=DataSourceBinding
2007-04-24 09:00:51,656 DEBUG [org.jboss.ejb3.ServiceDelegateWrapper] Creating persistence.units:ear=MyEar.ear,jar=MyApp.jar,unitName=myDS
2007-04-24 09:00:51,656 DEBUG [org.jboss.ejb3.ServiceDelegateWrapper] Created persistence.units:ear=MyEar.ear,jar=MyApp.jar,unitName=myDS
2007-04-24 09:00:51,656 DEBUG [org.jboss.system.ServiceController] Creating dependent components for: persistence.units:ear=MyEar.ear,jar=MyApp.jar,unitName=myDS dependents are: []
2007-04-24 09:00:51,656 DEBUG [org.jboss.system.ServiceController] starting service persistence.units:ear=MyEar.ear,jar=MyApp.jar,unitName=myDS
2007-04-24 09:00:51,656 DEBUG [org.jboss.ejb3.ServiceDelegateWrapper] Starting persistence.units:ear=MyEar.ear,jar=MyApp.jar,unitName=myDS
2007-04-24 09:00:51,671 DEBUG [org.jboss.ejb3.entity.PersistenceUnitDeployment] Found persistence.xml file in EJB3 jar
2007-04-24 09:00:51,687 INFO [org.hibernate.ejb.Version] Hibernate EntityManager 3.2.0.GA
2007-04-24 09:00:51,703 INFO [org.hibernate.cfg.annotations.Version] Hibernate Annotations 3.2.0.GA
2007-04-24 09:00:51,718 INFO [org.hibernate.cfg.Environment] Hibernate 3.2.0.ga
2007-04-24 09:00:51,734 INFO [org.hibernate.cfg.Environment] hibernate.properties not found
2007-04-24 09:00:51,734 INFO [org.hibernate.cfg.Environment] Bytecode provider name : javassist
2007-04-24 09:00:51,734 INFO [org.hibernate.cfg.Environment] using JDK 1.4 java.sql.Timestamp handling
2007-04-24 09:00:51,828 DEBUG [org.hibernate.ejb.Ejb3Configuration] 2007-04-20 09:31:26,390 DEBUG [org.hibernate.ejb.Ejb3Configuration] Processing PersistenceUnitInfo [
name: myDS
persistence provider classname: org.hibernate.ejb.HibernatePersistence
classloader: org.jboss.mx.loading.UnifiedClassLoader3@174a144{ url=file:/C:/jboss-4.0.5.GA/server/default/tmp/deploy/tmp30571MyEAR.ear ,addedOrder=47}
Temporary classloader: null
excludeUnlistedClasses: false
JTA datasource: org.jboss.resource.adapter.jdbc.WrapperDataSource@4eb98b
Non JTA datasource: null
Transaction type: JTA
PU root URL: file:/C:/jboss-4.0.5.GA/server/default/tmp/deploy/tmp30571MyEAR.ear-contents/MyJAR.jar
Jar files URLs []
Managed classes names [ <list of my classes>]
Mapping files names []
Properties [
hibernate.jacc.ctx.id: MyJAR.jar
hibernate.jndi.java.naming.factory.initial: org.jnp.interfaces.NamingContextFactory
hibernate.transaction.manager_lookup_class: org.hibernate.transaction.JBossTransactionManagerLookup
hibernate.cache.provider_class: org.hibernate.cache.HashtableCacheProvider
hibernate.dialect: org.hibernate.dialect.MySQLInnoDBDialect
hibernate.bytecode.use_reflection_optimizer: false
hibernate.jndi.java.naming.factory.url.pkgs: org.jboss.naming:org.jnp.interfaces
hibernate.bytecode.provider: javassist

Any ideas?

Thanks,

Bryan

1. Re: EntityManager Null when trying to inject into stateless

alrubinger Apr 25, 2007 11:49 AM (in response to bmant)
I couldn't say for sure, but a flag to me is that you're putting your EJBs in the WAR. I usually separate them into their own JARs with a:

<module> <ejb>ejbs-name.jar</ejb> </module>

...in META-INF/application.xml so the EJB3 Deployer knows to scan for them.

S,
ALR
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2. Re: EntityManager Null when trying to inject into stateless

bmant Apr 25, 2007 12:06 PM (in response to bmant)
Thanks for the fast response - but I am separating them - below is my application.xml.

<?xml version="1.0" encoding="UTF-8"?> <application id="Application_ID" version="1.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/application_1_4.xsd"> <display-name> MyEar</display-name> <module id="WebModule_1175089155093"> <web> <web-uri>FindResourcesService.war</web-uri> <context-root>FindResourcesService</context-root> </web> </module> <module id="EjbModule_1175102889765"> <ejb>MyEjbs.jar</ejb> </module>

I just did a little research - and I'm able to get the PersistenceContext injected - if I access my Stateless bean with a stand-alone java client (using InitialContext.lookup - and such).

So I think my issue is when a stand-alone java client - calls the webservice - then the webservice tries to create an instance of the Stateless session bean... I have to look into that now.

Do I have to add some Context persistence into my service call? I'll continue searching.

my client to call the service is this:

FindResourcesServiceLocator locator = new FindResourcesServiceLocator(); FindResourcesServicePort port = locator.getFindResourcesServicePort(); port.findResource()

and my webservice just initializes the SampleClass and calls a method in it:
SampleClass sample = new SampleClass(); sample.findResource();
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3. Re: EntityManager Null when trying to inject into stateless

bmant Apr 25, 2007 2:41 PM (in response to bmant)
Here is an update:

I was able to inject the PersistenceContext into my session bean by retrieving the LocalInterface class from the InitialContext within my web service java class.

SampleClass sc = null; InitialContext ic = new InitialContext(); sc = (ISampleClass)ic.lookup("MyEar/SampleClass/local");

I tried injecting the EJB at the class level - but that was always null.

@EJB (mappedName="MyEar/SampleClass/local") SampleClass sc;

I also tried just setting the mapped name to: SampleClass, MyEar/SampleClass and a bunch of other things - but none of them worked.

Is this the optimal solution to get my web service an instance of my stateless session bean from the container?
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4. Re: EntityManager Null when trying to inject into stateless

wolfc Apr 26, 2007 6:05 AM (in response to bmant)

http://www.jboss.com/index.html?module=bb&op=viewtopic&t=107353
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