jpa 2.0 not injecting EntityManager - jpa

Question

I have a simple implemenation of JPA 2.0 annotations that is not working. This is running in karaf 4.0.5 as a server. Below are listed the relevant excerpts from persistence.xml, blueprint.xml and the class. The exception is listed at the bottom.
The issue is that the EntityManager em is always null. I expected this to be injected by blueprint.
Can anyone point out where I've gone wrong?
Class
import javax.persistence.PersistenceContext;
import javax.transaction.Transactional;
#Transactional
public class LookupMfgService implements ILookupMfgService {
private static Logger logger = LoggerFactory.getLogger(LookupMfgService.class);
#PersistenceContext(unitName = "pu_motordb3")
private EntityManager em;
#Override
public List<String> getPreferredMfgNames() throws BusinessException {
List<String> list = new ArrayList<>();
try {
// em is null here so NPE thrown
TypedQuery<String> q = em.createNamedQuery("listMfgPreferredNames", String.class);
list = q.getResultList();
} catch (Throwable t) {
logger.error("Error selecting list of manufacturers", t);
throw JpaExceptionFactory.createGeneralError(t, this.getClass().getName());
}
return list;
}
public void setEm(EntityManager entityManager) {
logger.debug(this.getClass().getName() + ".setEntityManager()");
logger.debug("setEntityManager called with " + (entityManager == null ? "null" : entityManager.toString()));
this.em = entityManager;
}
}
DataSource.xml
<blueprint default-activation="eager"
xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:cm="http://aries.apache.org/blueprint/xmlns/blueprint-cm/v1.1.0"
xsi:schemaLocation="http://www.osgi.org/xmlns/blueprint/v1.0.0 http://www.osgi.org/xmlns/blueprint/v1.0.0
http://www.w3.org/2001/XMLSchema-instance http://www.w3.org/2001/XMLSchema-instance
http://aries.apache.org/blueprint/xmlns/blueprint-cm/v1.1.0 http://aries.apache.org/blueprint/xmlns/blueprint-cm/v1.1.0 ">
<bean id="dataSource" class="org.postgresql.ds.PGPoolingDataSource" destroy-method="close">
<property name="serverName" value="XXX"/>
<property name="user" value="XXX"/>
<property name="password" value="XXX"/>
<property name="dataSourceName" value="pgConnectionPool"/>
<property name="initialConnections" value="5"/>
<property name="maxConnections" value="50" />
</bean>
<service interface="javax.sql.DataSource" ref="dataSource">
<service-properties>
<entry key="osgi.jndi.service.name" value="MotorDB"/>
</service-properties>
</service>
</blueprint>
Blueprint.xml
<blueprint default-activation="eager"
xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:ext="http://aries.apache.org/blueprint/xmlns/blueprint-ext/v1.0.0"
xmlns:tx="http://aries.apache.org/xmlns/transactions/v2.0.0" xmlns:jpa="http://aries.apache.org/xmlns/jpa/v2.0.0"
xmlns:cm="http://aries.apache.org/blueprint/xmlns/blueprint-cm/v1.1.0"
xsi:schemaLocation="http://www.osgi.org/xmlns/blueprint/v1.0.0 https://osgi.org/xmlns/blueprint/v1.0.0/blueprint.xsd
http://aries.apache.org/blueprint/xmlns/blueprint-ext/v1.0.0 http://aries.apache.org/blueprint/xmlns/blueprint-ext/v1.0.0
http://aries.apache.org/xmlns/transactions/v2.0.0 http://aries.apache.org/xmlns/transactions/v2.0.0
http://aries.apache.org/xmlns/jpa/v2.0.0 http://aries.apache.org/xmlns/jpa/v2.0.0
http://aries.apache.org/blueprint/xmlns/blueprint-cm/v1.1.0 http://aries.apache.org/blueprint/xmlns/blueprint-cm/v1.1.0">
<jpa:enable />
<tx:enable />
<service id="mfgLookupService" ref="mfgLookupEntityImpl" interface="ILookupMfgService"/>
</blueprint>
Persistence.xml
<?xml version="1.0" encoding="UTF-8" ?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
version="2.0">
<persistence-unit name="pu_motordb3" transaction-type="JTA">
<provider>org.apache.openjpa.persistence.PersistenceProviderImpl</provider>
<jta-data-source>osgi:service/javax.sql.DataSource/(osgi.jndi.service.name=MotorDB)</jta-data-source>
Classes listed here
</persistence-unit>
</persistence>
Karaf log
2016-09-01 09:45:48,689 | INFO | PersistenceBundleTracker | 90 - org.apache.aries.jpa.container - 2.3.0 | Found persistence unit reference3 in bundle entity with provider org.apache.openjpa.persistence.PersistenceProviderImpl.
2016-09-01 09:45:48,695 | INFO | PersistenceBundleTracker | 90 - org.apache.aries.jpa.container - 2.3.0 | Found persistence unit pu_motordb3 in bundle entity with provider org.apache.openjpa.persistence.PersistenceProviderImpl.
2016-09-01 09:45:48,695 | INFO | PersistenceBundleTracker | 90 - org.apache.aries.jpa.container - 2.3.0 | Persistence units added for bundle com.easa.server.entity event 128
Exception
2016-08-31 18:42:49,286 | ERROR | nelWorkerThread0 | LookupMfgService | Error selecting list of manufacturers
java.lang.NullPointerException
at LookupMfgService.getPreferredMfgNames(LookupMfgService.java:93)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)[:1.8.0_91]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)[:1.8.0_91]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)[:1.8.0_91]
at java.lang.reflect.Method.invoke(Method.java:498)[:1.8.0_91]
at ch.ethz.iks.r_osgi.impl.ChannelEndpointImpl.handleMessage(ChannelEndpointImpl.java:1265)[69:ch.ethz.iks.r_osgi.remote:1.0.8.RC1_v20160823-2221]
at ch.ethz.iks.r_osgi.impl.ChannelEndpointImpl$2.run(ChannelEndpointImpl.java:315)[69:ch.ethz.iks.r_osgi.remote:1.0.8.RC1_v20160823-2221]
at ch.ethz.iks.r_osgi.impl.ChannelEndpointImpl$1.run(ChannelEndpointImpl.java:280)[69:ch.ethz.iks.r_osgi.remote:1.0.8.RC1_v20160823-2221]

Answer 1

Your datasource configuration appears to be missing. You are using osgi.jndi.service.name=MotorDB that is nowhere declared. So there is no service implementing javax.sql.DataSource
There has to be something similar to the following example which uses Oracle.
Change accordingly for other DBMS:
...
<bean id="dataSourceBeanMfgLookupService" class="oracle.jdbc.pool.OracleDataSource">
<property name="URL" value="???"/>
<property name="user" value="???"/>
<property name="password" value="???"/>
</bean>
<service id="dataSourceMfgLookupService" interface="javax.sql.DataSource" ref="dataSourceBeanMfgLookupService">
<service-properties>
<entry key="osgi.jndi.service.name" value="MotorDB" />
</service-properties>
</service>
...
Furthermore you may have to specify a persistence-provider in your persistence.xml. If you used hibernate with Oracle 10g it would look somehow like this:
<persistence xmlns="http://java.sun.com/xml/ns/persistence" ...>
<provider>org.hibernate.ejb.HibernatePersistence</provider>
...
<properties>
<property name="hibernate.dialect" value="org.hibernate.dialect.Oracle10gDialect" />
<property name="hibernate.temp.use_jdbc_metadata_defaults" value="false" />
...
Then you can link your datasource to your service:
<bean id="mfgLookupEntityImpl" class="LookupMfgService">
<jpa:context property="em" unitname="pu_motordb3" />
<tx:transaction method="*" value="Required" />
</bean>
If this still does not inject the EM provide a setter:
public void setEm(EntityManager entityManager) {
this.em = entityManager;
}
AFAIK there was/is a bug that property injection only worked if a setter was available.

Answer 2

The cause was an issue with karaf 4.0.5 and openjpa 2.4.1. It has been resolved in karaf 4.0.6