java - joinTransaction has been called on a resource-local EntityManager in ApacheCamel

Question

I am new to apache camel and I am testing camel-jpa to poll from table and display records

Following is main class

EntityManagerFactory    entityManagerFactory =  Persistence.createEntityManagerFactory("LoanServicePU");        
CamelContext camelContext = new DefaultCamelContext();

JpaComponent jpa = new JpaComponent();
jpa.setEntityManagerFactory(entityManagerFactory);
JpaTransactionManager myTM=new  JpaTransactionManager();
myTM.setEntityManagerFactory(entityManagerFactory);
jpa.setTransactionManager( myTM );
jpa.setCamelContext(camelContext);
camelContext.addRoutes(new JpaRouteBuilder());
camelContext.addComponent("jpa",jpa);
camelContext.start();
Thread.sleep(10000);
camelContext.stop();
System.out.println("Done");

Following is jparouter class

public void configure() throws Exception {
          from("jpa://com.pns.ab.model.LoanRequest?consumeDelete=false;"
                + "consumer.delay=2000;maxMessagesPerPoll=1000;"
                + "consumer.namedQuery=selectLoanRequests").to("stream:out");
}

I configured persistence.xml and its under META-INF, in fact in eclipse I start Java Project and then set JPA facet

persistence.xml

<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
    <persistence-unit name="LoanServicePU" transaction-type="RESOURCE_LOCAL">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
    <class>com.pns.ab.model.LoanRequest</class>
       <properties>
       <property name="eclipselink.target-server" value="None"/>
       <property name="javax.persistence.jdbc.driver" value="oracle.jdbc.OracleDriver"/>
       <property name="javax.persistence.jdbc.url" value="jdbc:oracle:thin:@127.0.0.1:1521:xe"/>
       <property name="javax.persistence.jdbc.user" value="vs"/>
       <property name="javax.persistence.jdbc.password" value="vs"/>
       <property name="eclipselink.logging.level" value="INFO"/>
      </properties>
  </persistence-unit>
</persistence>

But I am getting following error:

[main] INFO org.apache.camel.impl.DefaultCamelContext - Apache Camel 2.12.3 (CamelContext: camel-1) started in 1.426 seconds
[Camel (camel-1) thread #0 - jpa://com.pns.ab.model.LoanRequest] WARN org.apache.camel.component.jpa.JpaConsumer - Consumer Consumer[jpa://com.pns.ab.model.LoanRequest?consumeDelete=false%3Bconsumer.delay%3D2000&consumer.namedQuery=selectLoanRequests] failed polling endpoint: Endpoint[jpa://com.pns.ab.model.LoanRequest?consumeDelete=false%3Bconsumer.delay%3D2000&consumer.namedQuery=selectLoanRequests]. Will try again at next poll. Caused by: [javax.persistence.TransactionRequiredException - joinTransaction has been called on a resource-local EntityManager which is unable to register for a JTA transaction.]
javax.persistence.TransactionRequiredException: joinTransaction has been called on a resource-local EntityManager which is unable to register for a JTA transaction.
at org.eclipse.persistence.internal.jpa.transaction.EntityTransactionWrapper.registerIfRequired(EntityTransactionWrapper.java:91)
at org.eclipse.persistence.internal.jpa.EntityManagerImpl.joinTransaction(EntityManagerImpl.java:2081)

Answer 1

From the log

resource-local EntityManager which is unable to register for a JTA transaction

I conclude that the camel route is deployed to a JTA transaction environment but that in your persistence.xml you may use the default transaction-type which is RESOURCE_LOCAL instead of JTA.

EDIT:

With following setup, I could make it work:

1. Don't init the EntityManagerFactory and TransactionManager yourself, just do:

   final SimpleRegistry registry = new SimpleRegistry();
   final CamelContext context = new DefaultCamelContext(registry);
   context.addRoutes(new JpaSetupRouteBuilder());
   context.start();
   

2. In persistence.xml rename your persistence-unit to camel such as:

   <!-- setting the transaction-type to RESOURCE_LOCAL is optional as this is the default -->
   <persistence-unit name="camel" transaction-type="RESOURCE_LOCAL"> 
   

Yes, I know, this is not very satisfying.

EDIT:

If you don't want to or are not able to rename the persistence-unit to camel then you could set its name in the URI using the persistenceUnit option such as:

from("jpa://com.pns.ab.model.LoanRequest?consumeDelete=false"
         + "&consumer.delay=2000;maxMessagesPerPoll=1000"
         + "&consumer.namedQuery=selectLoanRequests"
         + "&persistenceUnit=LoanServicePU")
    .to("stream:out");

EDIT:

Or alternatively, use the Spring XML setup as described here.