Which of this keyword must be used to inherit a class * super this extent extends?
The super keyword in Java is a reference variable which is used to refer immediate parent class object. Show
Whenever you create the instance of subclass, an instance of parent class is created implicitly which is referred by super reference variable. Usage of Java super Keyword
1) super is used to refer immediate parent class instance variable.We can use super keyword to access the data member or field of parent class. It is used if parent class and child class have same fields. Test it NowOutput: In the above example, Animal and Dog both classes have a common property color. If we print color property, it will print the color of current class by default. To access the parent property, we need to use super keyword. 2) super can be used to invoke parent class methodThe super keyword can also be used to invoke parent class method. It should be used if subclass contains the same method as parent class. In other words, it is used if method is overridden. Test it NowOutput: In the above example Animal and Dog both classes have eat() method if we call eat() method from Dog class, it will call the eat() method of Dog class by default because priority is given to local. To call the parent class method, we need to use super keyword. 3) super is used to invoke parent class constructor.The super keyword can also be used to invoke the parent class constructor. Let's see a simple example: Test it NowOutput: animal is created dog is created Note: super() is added in each class constructor automatically by compiler if there is no super() or this().As we know well that default constructor is provided by compiler automatically if there is no constructor. But, it also adds super() as the first statement. Another example of super keyword where super() is provided by the compiler implicitly. Test it NowOutput: animal is created dog is created super example: real useLet's see the real use of super keyword. Here, Emp class inherits Person class so all the properties of Person will be inherited to Emp by default. To initialize all the property, we are using parent class constructor from child class. In such way, we are reusing the parent class constructor. Test it NowOutput: Accessing Superclass MembersIf your method overrides one of its superclass's methods, you can invoke the overridden method through the use of the keyword public class Superclass { public void printMethod() { System.out.println("Printed in Superclass."); } } Here is a subclass, called public class Subclass extends Superclass { // overrides printMethod in Superclass public void printMethod() { super.printMethod(); System.out.println("Printed in Subclass"); } public static void main(String[] args) { Subclass s = new Subclass(); s.printMethod(); } } Within Printed in Superclass. Printed in Subclass Subclass ConstructorsThe following example illustrates how to use the public MountainBike(int startHeight, int startCadence, int startSpeed, int startGear) { super(startCadence, startSpeed, startGear); seatHeight = startHeight; } Invocation of a superclass constructor must be the first line in the subclass constructor. The syntax for calling a superclass constructor is or: With Note: If a constructor does not explicitly invoke a superclass constructor, the Java compiler automatically inserts a call to the no-argument constructor of the superclass. If the super class does not have a no-argument constructor, you will get a compile-time error. If a subclass constructor invokes a
constructor of its superclass, either explicitly or implicitly, you might think that there will be a whole chain of constructors called, all the way back to the constructor of Which of these keyword must be used to inherit a class options super this extent extends?Inheritance uses the “extends” keyword to create a derived class by reusing the base class code.
Which of this keyword must be used to inherit a class in C++?Which of this keyword must be used to inherit a class? Explanation: None.
Which of these keywords Cannot be used to inherit a class?Explanation: None. 4. Which of these keywords can be used to prevent inheritance of a class? Explanation: Declaring a class final implicitly declared all of its methods final, and makes the class inheritable.
What is super () in Java?The super keyword refers to superclass (parent) objects. It is used to call superclass methods, and to access the superclass constructor. The most common use of the super keyword is to eliminate the confusion between superclasses and subclasses that have methods with the same name.
Which of these keywords is used to inherit from interface?4. Which of these keywords is used by a class to use an interface defined previously? Explanation: interface is inherited by a class using implements.
Which of this keyword must be used to inherit a class Option 1 extent Option 2 Super Option 3 this option 4 extends?The extends keyword indicates that the new class is derived from the base or parent class using inheritance, and export is not a keyword in Java. Hence, the correct answer is option (b).
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