private ServiceReference reference;
@Override
public void start( BundleContext bundleContext ) throws Exception {
reference = bundleContext.getServiceReference( GitHubUsers.class.getName() );
GitHubUsers gitHubUsers = (GitHubUsers)bundleContext.getService( reference );
GitHubUser user = gitHubUsers.getUser( "hstaudacher" );
System.out.println( user );
}