A little help needed

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Podstawy Java, Poziom 10, Lekcja 10

Dyskutowane

I find out correct solution but... someone could explain me why if I call (this.method1())

public void method2() {
           System.out.println("klasa A, metoda2");
           this.method1();
       }

and A.method1() is private then is called, otherside if A.method1() is publlic then C.method1() is called? I'm confused 🙃

public static class A {
        private void method1() {
            System.out.println("klasa A, metoda1");
        }

        public void method2() {
            System.out.println("klasa A, metoda2");
            this.method1();
        }
    }

    public static class B extends A {
        public void method1() {
            super.method2();
            System.out.println("klasa B, metoda1");
        }

        public void method2() {
            System.out.println("klasa B, metoda2");
        }
    }

    public static class C extends B {
        public void method1() {
            System.out.println("klasa C, metoda1");
        }

        public void method2() {
            System.out.println("klasa C, metoda2");
            super.method1();
        }
    }

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Thomas

Poziom 41 , Bayreuth, Germany

13 listopada 2022, 21:21

https://codegym.cc/forum/486 I commented my solution, too. I hope you understand what I meant

public class Solution {
    public static void main(String[] s) {
        A a = new C();
        a.method2(); // invoke Cm2
    }

    public static class A {
        private void method1() {
            System.out.println("A class, method1"); // now call history back and output last println in Bm1
        }

        public void method2() {
            System.out.println("A class, method2");
            method1(); // cause m1 is private, it is called here cause it is not overridden, otherwise plymorphism c object -> c class invoked
        }
    }

    public static class B extends A {
        public void method1() {
            super.method2(); // Am2
            System.out.println("B class, method1");
        }

        public void method2() {
            System.out.println("B class, method2");
        }
    }

    public static class C extends B {
        public void method1() {
            System.out.println("C class, method1");
        }

        public void method2() {
            System.out.println("C class, method2");
            super.method1(); // Bm1
        }
    }
}

Dejejen

Poziom 22 , Poland, Poland

14 listopada 2022, 05:18

Thank You. Yes, I understand, it's clear. Your answer brang me back to code and I realized: the object is C but object reference is A class... so obvious 😄