Jab about BPEL..

<!-- HelloWorld BPEL Process -->

<process name="HelloWorld"

         targetNamespace="http://samples.wspel.wordpress.com/helloworld"

         suppressJoinFailure="yes"

         xmlns:tns="http://samples.wspel.wordpress.com/helloworld"

         xmlns="http://schemas.xmlsoap.org/ws/2003/03/business-process/"

         xmlns:bpws="http://schemas.xmlsoap.org/ws/2003/03/business-process/"

         >

    <!-- List of services participating in this BPEL process -->

    <partnerLinks>

        <!--

        The 'client' role represents the requester of this service. It is

        used for callback. The location and correlation information associated

        with the client role are automatically set using WS-Addressing.

        -->

        <partnerLink name="client"

                     partnerLinkType="tns:HelloWorld"

                     myRole="HelloWorldProvider"

                     partnerRole="HelloWorldRequester"

                     />

    </partnerLinks>

    <!-- List of messages and XML documents used as part of this

         BPEL process

         -->

    <variables>

        <!-- Reference to the message passed as input during initiation -->

        <variable name="input"

                  messageType="tns:HelloWorldRequestMessage"/>

        <!-- Reference to the message that will be sent back to the

             requestor during callback

             -->

        <variable name="output"

                  messageType="tns:HelloWorldResultMessage"/>

    </variables>

    <!-- Orchestration Logic -->

    <sequence>

        <!-- Receive input from requestor.

             Note: This maps to operation defined in HelloWorld.wsdl

             -->

        <receive name="receiveInput" partnerLink="client"

                 portType="tns:HelloWorld"

                 operation="initiate" variable="input"

                 createInstance="yes"/>

        <!-- Generate content of output message based on the content of the

             input message.

             -->

        <assign>

            <copy>

                <from expression="concat('Hello ',bpws:getVariableData('input', 'payload','/tns:name'))"/>

                <to variable="output" part="payload" query="/result"/>

            </copy>

        </assign>

        <!-- Asynchronous callback to the requester.

             Note: the callback location and correlation id is transparently handled

             using WS-addressing.

             -->

        <invoke name="replyOutput"

                partnerLink="client"

                portType="tns:HelloWorldCallback"

                operation="onResult"

                inputVariable="output"

                />

    </sequence>

</process>