When reference variable of parent class refers to the object of child class, then it is known as

The parent class can hold reference to both the parent and child objects. If a parent class variable holds reference of the child class, and the value is present in both the classes, in general, the reference belongs to the parent class variable. This is due to the run-time polymorphism characteristic in Java.

Example

Following is an example −

 Live Demo

class Demo_base {
   int value = 1000;
   Demo_base() {
      System.out.println("This is the base class constructor");
   }
}
class Demo_inherits extends Demo_base {
   int value = 10;
   Demo_inherits() {
      System.out.println("This is the inherited class constructor");
   }
}
public class Demo {
   public static void main(String[] args) {
      Demo_inherits my_inherited_obj = new Demo_inherits();
      System.out.println("In the main class, inherited class object has been created");
      System.out.println("Reference of inherited class type :" + my_inherited_obj.value);
      Demo_base my_obj = my_inherited_obj;
      System.out.println("In the main class, parent class object has been created");
      System.out.println("Reference of base class type : " + my_obj.value);
   }
}

Output

This is the base class constructor
This is the inherited class constructor
In the main class, inherited class object has been created
Reference of inherited class type :10
In the main class, parent class object has been created
Reference of base class type : 1000

Explanation

A class named ‘Demo_base’ contains an integer value and a constructor that prints relevant message. Another class named ‘Demo_inherits’ becomes the child class to parent class ‘Demo_base’. This means, the ‘Demo_inherits’ class extends to the base class ‘Demo_base’.

In this class, another value for the same variable is defined, and a constructor of the child class is defined with relevant message to be printed on the screen. A class named Demo contains the main function, where an instance of the child class is created, and its associated integer value is printed on the screen. A similar process is done for the parent class, by creating an instance and accessing its associated value and printing it on the screen.

Updated on 14-Sep-2020 09:16:11

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Can I access a member variable of a child class through a reference to a parent class? With Solutions

Hello everyone, in this post we will examine how to solve the Can I access a member variable of a child class through a reference to a parent class? With Solutions programming puzzle.

class Card {
     //some stuff here
}
class Land extends Card {
    private boolean isBasic;
    public void isBasic(){
        return isBasic;
    }
}
class UsesCards extends SomethingElse {
    //initialize variables like SIZE
    Card cardList = new Card[SIZE];
    public void addCard(Card card){
        // Checking card's actual class.
        if (card instanceof Land && ((Land)card).isBasic()){
            //the rest
        }
    }
}

As we have seen, the Can I access a member variable of a child class through a reference to a parent class? With Solutions problemcode was solved by using a number of different instances.

Can you access child class with parent reference?

But since parent class reference variable points to sub class objects. So it is possible to access child class properties by parent class object if only the down casting is allowed or possible.

When parent class reference variable refers to child class object it is known as?

Polymorphism is the ability of an object to take on many forms. The most common use of polymorphism in OOP occurs when a parent class reference is used to refer to a child class object. Any Java object that can pass more than one IS-A test is considered to be polymorphic.

How do you access the variables of parent class in a child class in Python?

To access parent class attributes in a child class: Use the super() method to call the constructor of the parent in the child. The __init__() method will set the instance variables.13-Sept-2022

Can you pass values from child class to parent class in Java?

You can do this, but not the way you're coding it.15-Mar-2020

Can a parent access a child's school records?

Under education regulations, those with parental responsibility have the right to view a pupil's education record.

Can you inherit child class parent class?

Child or subclasses are classes that will inherit from the parent class. That means that each child class will be able to make use of the methods and variables of the parent class.05-Apr-2017

How do you access a private variable in child class?

We have used the getter and setter method to access the private variables. Here, the setter methods setAge() and setName() initializes the private variables. the getter methods getAge() and getName() returns the value of private variables.

Can an object of a child type be assigned to a variable of the parent type?

Yes—an object can be assigned to a reference variable of the parent type.17-Jul-1999

How do you call a method of parent class by an object of a child class in Java?

Use the super keyword to access parent class method In other words, the super keyword is used if the method is overridden. You override a method in the parent class by calling the same method in the child class. This process is known as method overriding.

How do you access member variables in a class?

To get the value of a class member variable, pass the class to one of the appropriate class member variable access functions. To get the value of an instance member variable, pass the object to the appropriate instance member variable access function. For example, in FieldAccess.

When reference variable of parent class refers to the object of class then it is known as?

Which polymorphism feature is related to parent and child class relationship in Java?

When a class extends a class which extends another class then this is called MCQ?

What is polymorphism and example?