Just building the app doesnt cause a bar to be created, you will have to run the deploy, either debug configuration, run configuration or via the bar-descriptor.xml "Export Release Build" functionality. Then it packages up the .so file
Ok I solved it. The problem was : at the bar-descriptor.xml under the 'advanced' option "current SDK target" was selected . I changed it to Blackberry OS 10.0.9.1101. and then I ran the project and the bar file was created. Thanks for the replies
Right click on the project. Run As->Run Configuration->Upload. In 'Deployment' option choose "Package applicatoin Bar file, But do not upload". It will create bar file but won't run the application. You can then change the configuration again to run it.