URGENT - very weird ClassCastException

Question

hello everyone,
im debugging now for about 4h and time is running out, i have no idea what the following exception could mean.
im calling several webservices and store their results (plain integer) in VC datastores, the datastores are properly populated.
the called webservice is an application-service with full logging, it doesnt throw any exception.
in NWA the log is blown up with this exception (something serious it seems, every stacktrace-step is an separate log-entry, very weird)
java.lang.ClassCastException: class java.lang.Integer:null incompatible with interface com.sapportals.connector.execution.structures.IAbstractRecord:library:[email protected]ParentClassLoader@693985fc@alive
at com.sap.tc.wd4vc.core.xgl2_2.infoactors.java.PortalWebserviceInfoactorXGL2_2_V_1_1_0_0.getNestedlogRecord(PortalWebserviceInfoactorXGL2_2_V_1_1_0_0.java:291)
at com.sap.tc.wd4vc.core.xgl2_2.infoactors.java.PortalWebserviceInfoactorXGL2_2_V_1_1_0_0.fillExecutionResult(PortalWebserviceInfoactorXGL2_2_V_1_1_0_0.java:317)
after (in time) this exception, the log is full with these entries:
findByRealKey, cVersDBObject == null for v=sap.com n=test/wkbt_impl t=DC s=NO_SUBSYS
the whole application-service runs smoothly but something is kicking this exception...
i checked every line of code for null-values, nothing. i double-checked each VC-connection for bogus mappings, nothing.
i do not see any light, any help very appreciated!
thanks,
kai

Answer 1

thanks for your answer atul, i already checked all passed values twice and didnt find anything null, all values seem to get properly passed, the applicationservice is properly executed and then the whole webdynpro-thing crashes.
have you already seen these log-entries? and what about exceptions with the stacktrace having seperate log-entries?
currently, i am recreating the VC-model from scratch. it seems using datastores as a poor-mans-alternative to JOINs messes things up....
so long,
kai