a final class can have subclass i.s. it can be extended
Can final classes be extended?
Classes marked as final can't be extended.
One example is the String class.
Consider the situation if we can extend the String class, override any of its methods, and substitute all the String instances with the instances of our specific String subclass.final classes can extend other classes but cannot be extended from.
You cannot declare a class that extends from a final class. abstract classes can only be extended by other classes and not used directly to create objects. final classes are meant to be uninheritable.
Can a class extend a subclass?
A class can extend only one other class.
To use the proper terminology, Java allows single inheritance of class implementation.
Later in this chapter, we'll talk about interfaces, which take the place of multiple inheritance as it's primarily used in other languages.
A subclass can be further subclassed.
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Chapter 11: Polymorphism
An object of subclass can be treated as an object of the super class. Abstract methods have no implementations because the abstract classes are. |
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MODULE III QUESTIONS SOLUTION 1. Explain the constructor
Though a final class cannot be extended it can extend other classes. In simpler It can have abstract and non-abstract methods (method with body). |
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class Tea extends Beverage {. } We get the following error: >javac Tea.java. Tea.java:3: Can't subclass final classes: class cert.Beverage class Tea extends |
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Inheritance and Polymorphism
10 Apr 2008 To introduce the notions of abstract methods abstract classes |
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25 Apr 2022 Java lets you write method code in an interface that you might not ... Note that a sealed class must have at least one subclass. |
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public final class FilledRectangle extends Rectangle { public int red green |
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Solutions to Exercises
extends. 3. A subclass can have only one superclass because Java doesn't support multiple implementation inheritance. 4. You prevent a class from being |
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Final and Abstract Classes 2 Restricting Inheritance Parent Child Inherited capability 3 Any attempt to inherit these classes will cause an error 5 Abstract Classes subclass £ We cannot declare abstract constructors or abstract static methods a kind of class—it contains methods and variables, but they have |
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Chapter 4 Inheritance in Java
extended is called base class, parent class or superclass, and the class that is You can see that in Java there is only one type of inheritance, you don't have to specify A final method is a method that cannot be overridden in a subclass |
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Chapter 11: Polymorphism
In Java, polymorphism is the ability of an object to take on many forms ▻ Objects of An object of subclass can be treated as an object of the super class ▻ Relying on (constructors are not inherited, non-private static methods are inherited |
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9 Classes, Inheritance and Abstraction
the last section of the book from an object oriented point of view This be inherited by subclasses (and can inherit from existing classes), • implement interfaces, they may return the number of instances of this class that have been created |
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MODULE III QUESTIONS SOLUTION 1 Explain the constructor
1 final class: We cannot extend a final class |
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Inheritance and Polymorphism
17 avr 2006 · declare something in a class to be private, we are saying that it can only be between direct subclasses/base class and indirect subclasses/base class 3 Crucial inherited method they override - otherwise we have an overload, not interface is implicitly public, static, and final, and must be initialized at |
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A A class can extend only one class but can implement many interfaces B An interface can C If you make a class final then you cannot extend the class D Constructor can be Direct subclass of Throwable in Java A Exception B Error C |
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The idea behind inheritance in Java is that you can create new classes that are built upon o Sub Class/Child Class: Subclass is a class which inherits the other class It If you make any class as final, you cannot extend it Example of final |
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Use extends keyword to tell that one class inherits from other class Superclass's constructor are not inherited ▻ Unlike Superclasses' constructors can (only) be invoked from public static void main(String[] args) { A a = new A (); a p(10); } } class B { Which instance field will we need to add to the CheckingAccount |
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Chapter 11 Abstract Classes and Interfaces
In other words, in a nonabstract subclass extended from an abstract class An abstract class can have instances created using the public static final int K = 1; |
