Problem with axis2 and QName class

Question

Hello,
We have deployed AXIS2 library with a library project (J2EE server component) as it is specify by a SAP guide. We deployed the sda file correctly and we know how to reference this library in Portal Application and J2ee Module WEB or EJB.
The problem is when we want to use internally javax.xml.namespace.QName is thrown an exception. This exception is shown bellow:
java.lang.LinkageError: loader constraints violated when linking javax/xml/namespace/QName class
at wpt.ConventerStub.populateAxisService(ConventerStub.java:52)
at wpt.ConventerStub.<init>(ConventerStub.java:100)
at wpt.ConventerStub.<init>(ConventerStub.java:89)
at wpt.ConventerStub.<init>(ConventerStub.java:140)
at wpt.ConventerStub.<init>(ConventerStub.java:132)
at com.eadscasa.axis2.Axis2Converter.doContent(Axis2Converter.java:26)
In the guide is said that we have to deploy a library project to avoid this problem but we still are getting it. I have realized that Qname class is a basic class into the JDK 1.4 and in different projects as AXIS2 making revision about this class.
How can I deploy these libraries (jars) without dependencies with SAP Portal libraries?
Is there any way to setup the classloader to avoid this error?
In the documentation about this kind of project it is said that you cannot deploy libraries (*.jar) with the same name. I donu2019t know if it happens the same with the class.
We have to develop web Services with Soap 1.2 specification, SAML etc and we need to develop this class because sap portal doesnu2019t support this kind o features.
Regards,
Daniel Urbano

Answer 1

Hi,
Firstly thanks for you reply. I generate the client with wsdl2java tool as it is mentioned in AXIS2 documentation and as you specified in your blog. After I follow the steps:
Step 1 - Generating the Axis2.war
Step 2 u2013 Modify the service *.aar file
Step 3 u2013 Create the J2EE library
Step 4 u2013 Create the J2EE application wrapping the web module axis2.war
We know how to make the step 1,2 and 3 but there is a little mess in the last step. Donu2019t worry about this because we got the general idea in this document. According to the guide the main problem is to solve a classloading conflict because it only can be loaded the libraries once and you need the AXIS2 libraries for *.arr and for the axis2 engine to be able to manage this module. This problem it is solved making a J2EE library Project and putting a reference to this library in the module, applications or project, which have to use AXIS2 libraries.
We have 3 different kind of projects that we can develop according to Sap Netweaver:
J2EE Project:
·     Web Module Project: Resulting a war file.
·     Enterprise Application Project: Resulting a ear file
·     EJB Module Project: Resulting a war file.
Portal Application
·     Portal Application Project: Resulting a par file.
In any project mentioned upper we know how to deploy these with a reference to this library project that previously we deployed successfully in the portal. But the problem is when we are going to check this module running it the server give us an exception.
java.lang.LinkageError: loader constraints violated when linking javax/xml/namespace/QName class
at wpt.ConventerStub.populateAxisService(ConventerStub.java:52)
at wpt.ConventerStub.(ConventerStub.java:132)
at com.eadscasa.axis2.Axis2Converter.doContent(Axis2Converter.java:26)
This exception is because exist classes into the axis2 libraries as javax.xml.namespace.Qname that are in SAP Portal libraries into the J2ee Server (JDK 1.4). This conflict is mentioned in the blog u201C360° View on enterprise SOAu201D where Michael Koegel, the author, says that if you want that AXIS2 libraries works you will have to work around with the dependencies of libraries.
The main problem in this point it is that we donu2019t know how to resolve this dependencies and if it is possible that other module of SAP Portal wonu2019t work fine if we change the base libraries. AXIS2 has newer classes than SAP Portal and it is possible that we can break other SAP Portal functions. In this case if we can not get that AXIS2 and SAP Portal co-exist in the same server we will probably have to change our way to get the enterprise objectives.
In order to resolve these dependencies we have found a SAP Note Number: 1138545. In this note it is said that we can setup the precedence class loader in the visual admin  into the deploy service. If you add your AXIS2 library at the beginning of StandardAplicationReferences variable in the deploy service, it is loaded the axis2 libraries first and it works the services but other portal functionality fails. This variable it is used to load the libraries precedence for all applications in the Server. If we could setup the class load precedence in a web module project or the system doesnu2019t take into account the server libraries for this module it will work perfectly.
If you could specify more the last point of your manual, I will appreciate it.
Regards,
Daniel Urbano