WS Adaptive Model: ClassCastException at WSGenericModelClass

Question

From a Web Dynpro application, I'm trying to connect to the KM through the webservice interface. For this, I'm using the Webservice Adaptive Model. And everything works fine, except the error handling.
For example, when I try to find resources, and I set a valid RID as a root RID parameter for the request, the resources found are retrieved, and I can list them from the context. But when I set a non-existing root ID, it throws a ClassCastException at the request.execute() method. And so on: at every "exceptional" case (for example trying to create an existing collection, or looking up a non-existing resource), instead of getting the real exception, I get a ClassCastException.
This ClassCastException has a null message, and null cause.
The stacktrace is:
at com.sap.tc.webdynpro.model.webservice.model.WSGenericModelClass.setRelatedObjectsForName(WSGenericModelClass.java:210)
at com.sap.tc.webdynpro.model.webservice.model.WSGenericModelClass.setRelatedObjectsForName(WSGenericModelClass.java:278)
at com.sap.tc.webdynpro.model.webservice.model.WSGenericModelClassExecutable.fillOutputParametersToMc(WSGenericModelClassExecutable.java:297)
at com.sap.tc.webdynpro.model.webservice.model.WSGenericModelClassExecutable.execute(WSGenericModelClassExecutable.java:97)
at com.sap.tc.webdynpro.model.webservice.gci.WSTypedModelClassExecutable.execute(WSTypedModelClassExecutable.java:46)
at de.dlh.ebase.dlh.appl.lsyh.im.wd.components.IMMain.kmCreateCollection(IMMain.java:425)
This last line (425) is where the request.execute() method is.
With the invocation log enabled, I can see that the SOAP response seems to be the right one: contains an OperationFailedException, with the exceptionName NameAlreadyExistsException (for example). And at least has a valid XML format (I checked).
The destination URL is set to:
http://<host>:<port>/RepositoryFrameworkWS/Config1?mode=sap_wsdl&style=document
(with a real host and port)
I tried without the mode sap_wsdl, with the same results.
RPC style doesn't work, because of the arrays, and the NWDS couldn't generate a model from the style rpc_encoded.
The Netweaver version is 7.0 SP13, I am using NWDS 7.0.13.
I tried to add different library references to the project (webservices, naming, tcsecdestinationsinterface, tckmcbc.uwlapi, tcwdwslib,webservices_lib, tcsecdestinationsservice, tcsecwssecservice, PORTAL:sap.com/com.sap.km.application),
I even tried to add the library sap.comtckmcbc.rf.wswsrf~bean.jar as a long shot, but I ended up with the same result.
I am needing to solve this, because I need to have the means to differentiate between "normal" operation errors and those of the exceptional nature.
For example: before creating a resource, I must check if the parent collection exists, If exists, fine, but if not, I must create the collection. Checking for existence might throw a "normal" (expected) exception, but if the user doesn't have the rights to do this operation, the application must know and act accordingly.
The webservice KM access is a requirement. (API access excluded, because in fact now I'm migrating from that)
Do you have any ideas?

Answer 1

There are 64k limits on several things (code per methods, constants, etc) in Java.
So i think the only solution would be to divide the WSDL file in more managable smaller pieces. But the webservice is a third party product, and so not in my responsibilty.
Werner