logging

AuthService.java

public class AuthService implements AuthServiceInterface {

    private Logger logger;

    // ...

    public void setLogger(Logger logger) {
      this.logger = logger;
    }

}

AuthServiceProvider.java

public class AuthServiceProvider implements ServiceProvider {

    @Override
    public Object create(Container container) throws Exception {
        Connection mysql = (Connection) container.get("mysql");
        Logger logger = (Logger) container.get("logger");
        AuthService auth = new AuthService(mysql);
        auth.setLogger(logger);

        return auth;
    }

}