In Oracle SOA Suite you can use the EJB adapter as a reference or service in your composite applications. The EJB adapter has a flexible binding integration, there are 3 ways for integrating the remote interface with your composite.
First you have the java interface way which I described here this follows the JAX-WS way. It means you need to use Calendar for your Java date types and leads to one big WSDL when you add a wire to a service component.
Second way is EclipseLink Moxy this solution is great when you can't change your java interfaces. Antony Reynolds made a great blogpost how to use EclipseLink moxy in Oracle Soa Suite.
The last way is generating a Service Data Object (SDO) service interface on your EJB Session Bean, This leads to a WSDL with a operation XSD and entity XSDs which can be used / read by the EJB Adapter ( no one big WSDL ). Use the java data types you want to use, JDeveloper can re-generate the SDO interface and no need to drag a dummy wire to refresh the EJB WSDL when you change the EJB Session bean.
In 2009 I already described this SDO feature but now with Patch Set 5 this SDO feature is finally working well. Before PS5 it was really hopeless.
So let's explain how this works in PS5. I already made a simple HR JPA Model project with a EJB Session Bean.
Before we start we need to think about lazy and eager object loading. In this Department entity I will eager retrieve the manager and employees of this department.
In the Employee entity I will use the Lazy fetch type on the department attribute.
Just like the java interface mapping way we can't have circular references between department and employees XSD. We need to break the loop so add @XmlTransient to the getter of the department attribute of the employee entity. ( now the department element will be skipped in the employee XSD )
Select your EJB Session Bean ( Right Click ) and select Create Service Interface.
When we want to use this SDO interface in Oracle SOA Suite we need to enable the Configure as an ADF-BC Service. This will add the necessary SDO annotations on the Remote Interface.
With this as result
The generated Department entity XSD.
The EJB SDO Session Bean WDSL
JDeveloper adds PortableWebService annotation to the EJB Session bean.
The remote interface with all the web annotations on a SDO method.
Also when you want the same behaviour as a Database adapter you can force to start a new transaction and not take part in the BPEL transaction. This way you can see if the transaction is successful at the end of the invoke instead of the end of BPEL.
JDeveloper also adds code to the EJB Session Bean to marshall and unmarshall the java or xml.
Think about which attributes can be empty else you will get some null pointer exceptions.
Also it will load all the SDO XSDs in the EJB Session Bean. If you don't have circular XSD references then loading should be successful.
In a java client we can test the SDO interface ( this will not use the remote interface annotations) by first loading the XSDs and invoking a SDO session bean method. Loading of the XSDs is necessary else you will get some EclipseLink objects instead of the department of employee objects.
Deploy the EJB to the SOA Suite Server and also generate an interface jar which does not contain the meta-inf folder and the Bean.
Now is the time to configure the EJB adapter in Oracle SOA Suite. Drag the EJB Adapter to the reference side of the composite.
Lookup the jar and the WSDL. The wizard will copy the interface jar and WSDL, XSDs to your project.
Fix the jndiName bug in the reference service, go to source mode of the composite.xml , rename the uri attribute to jndiName.
Finish your composite and deploy it. When you go for a test drive you will see something like this.
Here you can download my example project.