@SpringBootApplication
class SpringBootKotlinExampleApplication(private val accountRepository: AccountRepository,
                                         private val messageRepository: MessageRepository) : CommandLineRunner {
  override fun run(vararg p0: String?) {
    //.. some logic  
  }
}

fun main(args: Array<String>) {
    runApplication<SpringBootKotlinExampleApplication>(*args)
}

@Service
@Transactional
class MessageService constructor(val messageRepository: MessageRepository){

  @Transactional(readOnly = true)
  fun findAll() : List<Message> {
    return messageRepository.findAll()
  }
  // ... some logic 
}