java - OSGI classcast exception on felix -

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i'm new osgi , trying functional proof of concept together.

the setup common api created in bundle creatively named common-api.jar no bundle activator, exports it's interfaces. 1 of interest in situation databaseservice.java.

i have second bundle called systemx-database-service. implements database service interface. works fine in activator of implementation bundle test connection database , select arbitraty values. register service want available other bundle's so:

   context.registerservice(databaseservice.class.getname(), new systemdatabaseserviceimpl(context), new properties());

the basic idea being when service reference database service you'll systemdatabaseservice implementation.

when inspect service output this:

-> inspect s c 69 system database service (69) provides services: ---------------------------------------------- objectclass = za.co.xxx.xxx.common.api.databaseservice service.id = 39

which lead me believe if in test bundle: 

context.getservice(context.getservicereference(databaseservice.class));

i should instance of databaseservice.class, alas no such luck. seems cannot find service. stick me here story gets stranger.

figuring there no go wrote monstrosity:

 (bundle bundle : bundles) {         if (bundle.getsymbolicname().equals("za.co.xxx.xxx.database-service")) {             servicereference[] registeredservices = bundle.getregisteredservices();             (servicereference ref : registeredservices) {                 databaseservice service = (databaseservice) context.getservice(ref);                // use service here.                 }             }         }     }

now can see service reference, error

java.lang.classcastexception: za.co.xxx.xxx.database.service.impl.systemdatabaseserviceimpl cannot cast za.co.xxx.xx.common.api.databaseservice

which crazy since implementation implements interface!

any appreciated. please keep in mind i'm new @ osgi way of thinking whole approach here might flawed.

oh. if wants manifests can post them. , i'm using maven-bnd-plugin build , executing on felix.

thanks

nico

the test bundle must resolve same import of databaseservice interface systemdatabaseserviceimpl. if not occur, getservicereference documents return null if service found. locating bundle manually , attempting locate service , cast, you're showing why getservicereference behaves in way: if returned arbitrary services, java casts fail.

i recommend printing databaseservice.class.getclassloader() in both impl bundle , test bundle prove if they're same bundle. if they're not, need adjust osgi manifest.mf metadata ensure have consistent view of interface class.

for example, databaseservice interface included in both test , impl bundles? if yes, need move interface either impl bundle (and export-package) or third interface bundle , export-package. then, adjust other bundles import-package.


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