Example with Spring

Create basic spring application:

@SpringBootApplication
public class SpringApp {

    @Inject
    private SomeEntityService service;

    public static void main(String[] args){
        SpringApplication.run(SpringApp.class);
    }

}

And a rudder integrator:

public static class SpringRudderApp
    extends SpringApp
    implements ApplicationListener<ApplicationReadyEvent>,
                RudderApplication<SpringApp> { (1)

    private static Consumer<SpringApp> callback;

    public static void setReadyCallback(final Consumer<SpringApp> callback) {(2)
        SpringRudderApp.callback = callback;
    }

    @Override
    public void onApplicationEvent(final ApplicationReadyEvent applicationReadyEvent) {
        callback.accept(this); (3)
    }
}

1	Implement `RudderApplication<T>` with base class as a generic `T` parameter
2	Don’t forget about `setReadyCallback` method, it’s needed by rudder to start the app
3	Notice the application ready event listener. It notifies the rudder host (and, thus, rudder client) that application started and is ready for being worked with.

Add an entity, a repository and a service:

@Entity
public class SomeEntity {
    //...
}

@Repository
public interface SomeEntityRepository extends JpaRepository<SomeEntity, Long> {
    //...
}

@Service
public class SomeEntityService {

    private final SomeEntityRepository repo;

}

Now we can start application:

public class SpringSample {

    public static void main(String[] args) throws Exception {
        final var clazz = SpringRudderApp.class;
        final var container = new ContaineredApplication<>("Sasuke", "adoptopenjdk/openjdk11:x86_64-ubuntu-jdk-11.28", clazz, List.of());

        container.start();

        final SpringApp application = container.getApplication();

        // we can get service
        final SomeEntityService service = application.getService();

        // and a repo
        final SomeEntityRepository repo = service.getRepo();

        // use them
        final SomeEntity save = service.createSome("Test");

        final Long id = save.getId();

        // and inspect the result of usage
        final SomeEntity some = service.findSomeEntityById(id);

        System.out.println(some.getTitle());

        final List<SomeEntity> all = repo.findAll();
        final SomeEntity someEntity = all.get(0);

        System.out.println(someEntity.getTitle());

        container.stop();
    }


}

Full sources of example