访问控制举例

package lianxii;

class Parent {

    private final int f1 = 1;
    int               f2 = 2;
    protected int     f3 = 3;
    public int        f4 = 4;

    private void fm1() {

        System.out.println(f1);
    }

    void fm2() {

        System.out.println(f2);
    }

    protected void fm3() {

        System.out.println(f3);
    }

    public void fm4() {

        System.out.println(f4);
    }

    //    public static void main(String[] args) {
    //
    //        Parent b = new Parent();
    //        b.fm1();
    //        b.fm2();
    //        b.fm3();
    //        b.fm4();
    //        b.getClass();
    //    }
}

class Child extends Parent {

    private final int c1 = 21;
    public int        c2 = 22;

    private void cm1() {

        System.out.println(c1);
    }

    public void cm2() {

        System.out.println(c2);
    }

    public void main(String[] args) {

        int i;
        Parent p = new Parent();
        i = p.f2;
        p.fm2();
        Child c = new Child();
        i = c.c1;
        i = c.c2;
        c.cm2();
        c.cm1();
    }
}