Oracle SOA Suite uses callbacks for both interface.wsdl and interface.java. However, the concept of callbacks does not exist in the spring framework. For Oracle SOA Suite services and references, a callback is specified (in the metadata) as a second port type for interface.wsdl or a second Java name for interface.java. The spring metadata has only sca:services and sca:references and no way to specify a callback.

To design a callback with spring, you must provide sca:services and sca:references with a specific name. If you create both a sca:service and sca:reference using the naming conventions of someService and someServiceCallback, Oracle SOA Suite recognizes this convention and creates a single service or reference with a callback.

For example, assume you create the syntax shown in the following example in the spring context file with the spring editor in Oracle JDeveloper:

<sca:service  name="StockService"
 type="oracle.integration.platform.blocks.java.callback.StockService"
 target="impl" />
 <sca:reference  name="StockServiceCallback"
 type="oracle.integration.platform.blocks.java.callback.StockServiceReply" />

Oracle SOA Suite automatically creates a single service as shown in the following example:

    <service name="StockService">
      <interface.java
 interface="oracle.integration.platform.blocks.java.callback.StockService"   
           callbackInterface="oracle.integration.platform.blocks.java.callback.StockServiceRe
ply"/>
    </service>

In the SOA Composite Editor, if a spring interface.java with a callback interface is dragged to a WSDL component (for example, Oracle BPEL Process Manager, Oracle Mediator, or others), a WSDL with two port types is generated (technically, a wrapper WSDL, which is a WSDL that imports two other WSDLs, each having a single port type).

If you drag a WSDL or Java interface that has a callback to a spring service component, a single interface is displayed in the SOA Composite Editor. However, inside the spring editor, you find both a sca:service and sca:reference that have the same naming conventions (someService and someServiceCallback).