Wie wird die Typumwandlung bei Mehrfachvererbung in Java implementiert?

[Sachinbhatt]

Hello dear forum,
I'm new here, so first of all I'm glad that this forum exists. my last hope

I need assistance in how to access the superclass data member using this keyword. I know that cast is used

but I don't know how to implement it. Help me!!

 

[yfons123]

if you want access a variable of your superclass instead of the one defined in your child class use super

public class X{
    protected int x;
}

public class Y{
    public Y (){
        super.x = 10;
    }
}

or formulate your question more properly with code

EDIT:

public class Main {
    public static void main(String[] args) {
        var y  = new Y();
        System.out.println(y.get());
    }
}
class X{
    public int x = 10;

}
class Y extends X{
    public int x = 5;
    public int get() {
        return super.x + x;
    }
}

 

[yfons123]

additonally to that multiple inheritance in java is only possible with default methods in interfaces , there is a special syntax you need to use and google

public class Y implements X,Z
{
    public Y(){
        super.X.doStuff();
    }
}

afaik it was something like that to use interface multi inheritance

 

[KonradN]

You mean accessing a hidden member?

You can access a hidden Member through a cast on this:
((SuperClass)this).hiddenMember

This is even possible outside the Class because late binding is only available with methods.

So if class A has member i and B derives from A and also has a member of i, then you can access the i inside A though a cast, too.

Edit: quick example so the last could be understood more easily:

class A {
    int i = 1;
}

class B extends A {
    int i = 2;
}

class Test {
    public static void main (String... args) {
        B b = new B();
        System.out.println(((A)b).i); // Shows i inside A => 1
    }
}