Workaround of bug in integration of db4o and axis2

I have been trying to solve the problem described in my last post.

I tried different versions of tomcat and Db4o which did not help me out. I posted this problem in forum of Db4o to ask for help. However, no one supplied right solution. I tried countless possible solutions. Finally, I got it to work. Following is the procedure how I discovered my solution.

To enhance speed of development , I tried to find some software support. I have been using Eclipse as my IDE. So naturally WTP(Web Tool Platform) is a great plug-in to support development of web applications in Eclipse. WTP provides support for Tomcat and Axis2 which are being used in my project. Here(http://www.eclipsecon.com/webtools/community/tutorials/BottomUpAxis2WebService/bu_tutorial.html) is a great tutorial about how to deploy and start Axis2 web service in Eclipse.

Then I doubt that the problem maybe results from Axis2. So I decided to write a simple servlet to do similar job. In other words, Axis2 was not used. And test result showed that everything worked correctly with Db4o. So this meaned that it is highly possible that Axis2 is cause of the problem. I did further investigation to uncover what is wrong under the hood. I built the same Axis2 service in Eclipse and deployed the service to Eclipse's temporary publish directory. Surprisingly, it worked!!! However, if I built web service using ADB(Apache Databinding) in Axis2, wrapped it to a .aar archive file and deployed it into specific directory (services), it did not work!!! So, I made sure that the procedure of deployment of Axis2 web service in Eclipse MUST be different from what I did before. Finally, I found that Eclipse does not wrap web service implementation into a .aar archive file. Instead the deployment directory layout is:

axis2
    - WEB-INF
        - lib
        - conf
        - services
            - Sample                        //Sample is the name of this web service
                - META-INF
                    - services.xml       //this file describes the information of this web service.
        - classes
            - package                     //this is path corresponding to package
                - *.class                    //These .class files are implementation of web service.
    - META-INF
    - axis2-web

The original layout is:
axis2
    - WEB-INF
        - lib
        - conf
        - services
            - Sample.aar               //the .aar archive file
        -classes
    - META-INF
    - axis2-web

Difference is highlighted in blue.
The services.xml is also different. The new services.xml is:

<service name="Sample" >
    <description>
        Please Type your service description here
    </description>
    <messageReceivers>
        <messageReceiver mep="http://www.w3.org/2004/08/wsdl/in-only" class="org.apache.axis2.rpc.receivers.RPCInOnlyMessageReceiver" />
        <messageReceiver  mep="http://www.w3.org/2004/08/wsdl/in-out"  class="org.apache.axis2.rpc.receivers.RPCMessageReceiver"/>
    </messageReceivers>
    <parameter name="ServiceClass" locked="false">package.Sample</parameter>
</service>

Besides, in my previous using of Axis2, I used tool provided by Axis2 to construct automatically a stub class and some other auxiliary classes of client side. Then I added my implementation code to that stub class (this stub class contains Axis2-specific stuff). In this new deployment, I did not rely on any Axis2-specific functionality. I just wrote my implementation and compiled it into .class files. And then copied these .class files to directory ${TOMCAT_ROOT}/axis2/classes/package-path/. In addition, I needed to manually create and edit corresponding services.xml file. In my previous deployment, this file is generated automatically by Axis2 tool.
To sum up, this new deployment method eases development of web service because no Axis2-specific stuff is involved during development. The drawback is it is not compact considering that those files are scattered in different places. With regard to this deployment, I did not find much useful information on web. Maybe this method is not recommended, who knows...

However, I have no choice because only one of them works well.