item 24 Jung inchul - JAVA-JIKIMI/EFFECTIVE-JAVA3 GitHub Wiki

public class StaticCar {
    static String _where="I am a Car from Germany!";
    Country _country;            // object of inner class country
    StaticCar(){
        _country=new Country();    // instantiate the inner class
    }
    static class Country {       // static member inner class
        String showCountry() {
            return _where;
        }
    }

    public static void main(String[] args) {
    StaticCar myCar= new StaticCar() ;  // instantiated object of class StaticCar
    System.out.print("Access through an Country reference");
    System.out.println(" created in an object of a StaticCar:");
    System.out.println(myCar._country.showCountry());

    // instantiated object of class StaticCar.Country
    StaticCar.Country country= new StaticCar.Country();
    System.out.println("Access through an Country reference that is local:");
    System.out.println(country.showCountry());

    }
}

public class MySet<E> extends AbstractSet<E> {
    ... // 생략

    @Override public Iterator<E> iterator() {
    return new MyIterator();
    }

    private class MyIterator implements Iterator<E> {
    ...
    }
}

interface Inter {
    public void hi();
}

class Anony {
    public void f() {
        System.out.println("Anony.f() 호출.");
    }
}

public class Test {
    private Integer number;

    public void nonStaticMethod(){
        Inter ob2 = new Inter() {
            public void hi() {
                System.out.println("비 정적문맥 메소드 호출" + number);
            }
        };
    }

    public static void staticMethod() {
        Inter ob2 = new Inter() {
            Integer number2 = 1;
            public void hi() {
                System.out.println("정적문맥 메소드 호출" + number); // comile Error
            }
        };
    }

    public static void main(String[] args) throws Exception {
        //Inter ob1 = new Inter(); //Compile Error!!!
        Inter ob2 = new Inter() {
            public void hi() {
                System.out.println("안녕하십니까?");
            }
        };

        ob2.hi();

        Anony a1 = new Anony();
        Anony a2 = new Anony() {
            public void f() {
                System.out.println("이히힛.");
            }
        };

        a1.f();
        a2.f();
    }
}

static List<Integer> intArrayAsList<int[] a) {
    Objects.requireNonNulkl(a);

    // 다이아몬드 연산자를 이렇게 사용하는 건 자바 9부터 가능하다.
    // 더 낮은 버전을 사용한다면 <Integer>로 수정하자.

    return new AbstractList<>() {
    @Override public Integer get(int i) {
        return a[i];
    }

    @Override public Integer set(int i, Integer val) {
        int oldVal = a[i];
        a[i] = val;
        return oldVal;
    }

    @Override public int size() {
        return a.length;
    }
}