// Get the service reference
ServiceReference<SimpleService> sref = context.getServiceReference(SimpleService.class);
assertNotNull("ServiceReference not null", sref);
// Get the service for the reference
SimpleService service = context.getService(sref);
assertNotNull("Service not null", service);
// Invoke the service
int sum = service.sum(1, 2, 3);
assertEquals(6, sum);
// Stop the bundle
bundle.stop();
assertEquals("Bundle RESOLVED", Bundle.RESOLVED, bundle.getState());