[スプリングコア原理]-4

モノトーンモード

public class SingletonService {

    private static final SingletonService instance = new SingletonService();

    public static SingletonService getInstance(){
        return instance;
    }

    private SingletonService(){

    }
}

    void singletonServiceTest(){
        SingletonService singletonService1 = SingletonService.getInstance();
        SingletonService 
        //...

        System.out.println("singletonService1 = " + singletonService1);
        //...
        Assertions.assertThat(singletonService1).isSameAs(singletonService2);
    }

短所

たんトンコンテナ

    void springContainer(){

        ApplicationContext ac = new AnnotationConfigApplicationContext(AppConfig.class);
        MemberService memberService1 = ac.getBean("memberService", MemberService.class);
        //...

        Assertions.assertThat(memberService1).isSameAs(memberService2);
    }

モノトーンの注意点