Introduction to Types of Inheritance in Java

If you are looking for types of inheritance in java so you are in the right place. Today you are going to dive deep into types of inheritance in Java. As we all know Java is an object-oriented programming language that is used globally in the development of websites and applications etc. So inheritance comes in object-oriented programming which belongs to a mechanism, based on an object and class over another object.

Inheritance in java is the most important point of oops as object-oriented programming. It permits us to inherit the use of properties from one class into another class. In this section, we will talk over types of inheritance in Java in-depth with real-life examples. Also, we will produce Java programs to apply the generalization of different types of inheritance. You are going to explore the types of inheritance in java such as:

• Single Inheritance
• Multiple Inheritance
• Multi-Level Inheritance
• Hierarchical Inheritance
• Hybrid Inheritance

For your kind information, you are going to grab two other types of inheritance in java that are only available through a combination of class and interface inheritance.

• First is multiple inheritances, when a single child class inherits from multiple parent classes.
• The second is hybrid inheritance, a bunch of two or more than one kinds of inheritance known as hybrid inheritance.

Also Read : What is Adapter Class in Java?

What is Inheritance?

Inheritance in java is a core concept that requires the properties of one class to another class like a guardian. For example the relationship between father and son. Or also we can say that the properties derived from one class to another class are a term inheritance. The class inherits shared attributes and methodologies from another class. With the concepts of inheritance in java, the data in a program can be organized chronologically.

In Java, the inheritance permits stoners to produce that classes and properties according to their use. For your kind information it was created in the year 1969 for the simula it was programming language of computing center in Oslo. Here we are going to talk about it in Java but it is available in all object-oriented programming languages such as PHP, C++, and Python. The term inheritance is specially used for both class and prototype. Further, we will read types of inheritance in Java.

A Few Vital Terminologies Related to the Concept are:

• Class: It’s elaborated as a bunch of objects sharing common properties. It is a kind of blueprint of produced objects.
• Sub Class: Even referred to as a derived or extended subclass, this category inherits the options from another class. Together with the inheritable fields and strategies, the class generated from the category will add fields and strategies of its own.
• Super Class: The superclass also known as the parent class represents the category whose options are units inheritable by a subclass.
• Reusability: As the name is defined, it is a technique of reusability that permits the user to make a class while using the methods of the new class. having the fields or strategies of associate in nursing already existing class. It permits reusing the code.

These all concepts terminologies are the basics in types of inheritance in Java.

Syntax

class derived_class extends base_class

{

//methods

//fields

}

General Format

class​ superclass

{

// superclass data variables

// superclass member functions

}

class​ subclass ​extends​ superclass

{

// subclass data variables

// subclass member functions

}

For your kind information inheritance uses the “extends” keywords to produce derived classes while using the Base class. Extending keywords indicates the class to another class.

Extends Keyword

As already shared earlier, that extended keyword is the indicator of a class to another class, like receiving the legacy from our forefathers by genetic inheritance of enzymes. It means class B inherits the attributes and methods from class A. It means now class A is a superclass and class B is playing the role of a subclass.

For example in program: 

class Base

{

public void M1()

{

System.out.println(“Base Class Method”);

}

}

class Derived extends Base

{

public void M2()

{

System.out.printIn(“ Derived Class Methods “);

}

}

class Test

{

public static void main(String[] args)

{

Derived d = new Derived(); // creating object

d.M1(); // print Base Class Method

d.M2(); // print Derived Class Method

}

}

OUTPUT

Base class method

Derived class method

Types of Inheritance in Java

There are the miscellaneous types of inheritance in java:

• Single Inheritance
• Multiple Inheritance
• Multi-Level Inheritance
• Hierarchical Inheritance
• Hybrid Inheritance

Single Inheritance 

As we can say that producing a parent class from a single base class is known as single inheritance. Because it requires only a single class to create the superclass. In inheritance, we can use the variable of superclass and subclass methods and attributes without any conflict. It comes in types of inheritance in Java.

Coding example of single inheritance:

class A

{

int a, b;

void display()

{

System.out.println(“Inside class A values =”+a+” ”+b);

}

}

class B extends A

{

int c;

void show()

{

System.out.println(“Inside Class B values=”+a+” “+b+” “+c);  }

}

class SingleInheritance

{

public static void main(String args[])

{

B obj = new B(); //derived class object

obj.a=10;

obj.b=20;

obj.c=30;

obj.display();

obj.show();

}

}

OUTPUT

Inside class A values = 10 20

Inside class B values = 10 20 30

Multiple Inheritance

When there is a chain of various inheritances it is called multiple inheritances. Simplifying derived classes from the multiple cl
ass is known as multiple inheritances. So here it can be one class at least or more than that it can be more classes of a superclass. Multiple inheritances are available in object-oriented programming, but it is not available in Java. it does not come in types of inheritance in Java.

Java programmers are always fascinated by using multiple inheritances in a few conditions. There are interfaces concepts by which java programmers use it in multiple inheritances. Why are multiple inheritances not supported in Java? Behind this, there is a simple reason that is to stop ambiguity. When class A extends to B and classes A and C apply the same method as B class.

Multi-Level Inheritance

Multilevel inheritance in Java adds the two classes or more than it and also it extends to another class that is already extended. Suppose there is class A which extends from class B and B extends from C is known as multilevel inheritance. Below is a graph to make you understand. We can take the example of classes such as class food, class pizza, class coca-cola so here parent class is food class and class pizza extended to coca cola class. It comes in types of inheritance in Java.

Hierarchical Inheritance

So here Hierarchical Inheritance in Java is something that when two child classes extend to a single parent class is known as hierarchical inheritance. Or if a single parent class has a two-child class then also it is known as hierarchical inheritance.

Let’s have the examples: in parent class vegetables now take the child class as potato, tomato, and cucumber. In this Hierarchical Inheritance in Java, class potato, class tomato and cucumber are the extended class of vegetables. It also comes in types of inheritance in Java.

Hybrid Inheritance

A combination of inheritance is known as a hybrid inheritance in Java. It is a kind of inheritance that compiles the single inheritance and multiple inheritances. As we know that hybrid inheritance in java is not supported with it so here it can be also used through interfaces.

We have identified that there are two types of inheritance: single inheritance and hierarchical inheritance. It does not come in types of inheritance in java.

Inheritance Program in Java

As we have read about types of inheritance in Java so let’s try to understand it in programming. In parent class objects if we use variables and methods it will get an error.

Due to the complexity of the language, Java does not support multiple inheritances.

An example of inheritance in Java:

class Parent

{

public void M1()

{

System.out.println(“Parent Class Method”);

}

}

class Child extends Parent

{

public void M2()

{

System.out.println(“Child Class Method”);

}

}

class Inh_In_Java

{

public static void main(String[] args)

{

Parent p=new Parent();

p.M1();

p.M2();​ // error-wrong way to call derived class method

}

}

Output 

Symbol: method M2 ()

Location:  variable p of parent

1 error

Applications of Inheritance in Java

It is used to relate them with each other when it comes to two classes or more than one.

Method Overriding in Java 

• If the subclass has the same methodologies to apply then this method comes in an action which is method overriding in java.
• It has the same methods as the parent class and with the help of using it will get runtime morphosis.
• The overriding method helps to provide the function in types of inheritance in java.

Code Reuse

As we have discussed, it is a mechanism that is based on subclass and class. It is also known as software reuse. Unfortunately, the subclass keeps all the functions of the base class, child class might override some method few ductions. It means to replace the parent class with itself. The base class comprises functions to compute the sum of the squares between two figures. In most areas, inheritance of class for the core purpose of software reuse has fallen out of favor.

Difference between Inheritance and Subtyping 

Inheritance is related to although clear-cut subtyping. It provides a type to substitute for different or removal and initiated as in the relationship between subtypes. If inheritance is not supported in programming languages as a subtyping mechanism, it does not require behavioral subtyping. Overall it is possible when the parent class is expected while using a derived class whose object will behave incorrectly. It will clear you towards types of inheritance in java.

Design Constraints 

While using it considerably in designing a program imposes certain constraints.

For instance, consider a class Person that contains a person’s name, date of birth, address, and phone number. We can define a child class of Person as called Student that contains the person’s grade point average and classes are taken, and another child class of Person called worker that contains the person’s job- title, employer, and payment.

In defining this (inheritance) scale we’ve previously defined certain restrictions, not all of which are desirable.

Singleness

While Using single this (inheritance), a class can inherit from only one superclass. Continuing the instance given above, a person can be either an aspirant or a worker, but not both. Using inheritance in a multiple-way incompletely solves this problem, as one can also define a StudentEmployee class that inherits from both aspirant and worker. Still, in utmost accomplishments, it can still inherit from each superclass only formally, and therefore, doesn’t support cases in which a pupil has two jobs or attends two institutions. Its model available in Eiffel makes this possible through support for repeating it (inheritance).

Static

The scale of an object is fixed in the object of instantiation when the object’s type is named and doesn’t change with time. For instance, the graph of inheritance doesn’t allow a scholar object to be a worker object while retaining the state of its Person superclass. Some have blamed it, contending that it locks programmers into their original design principles.

Visibility

Whenever a customer program has access to an object, it generally has access to all the object’s superclass data. Indeed if the superclass has not been declared public, the customer can still cast the object to its superclass type. For instance, there’s no way to give a function a pointer to a Student’s grade point average and paraphrase without also giving that function access to all of the particular data stored in the aspirants’ Person superclass. Numerous contemporary languages, including C and Jav
a, give a” defended” access modifier that allows child classes to enable the data, without allowing any program outside the chain of visibility to enable it.

Conclusion

Let’s talk about the journey from where we are coming to the types of inheritance in Java. We have discussed the important types of inheritance in Java with all components of Inheritance in java. Starting from the introduction to the class and also the application while giving the coding example of java. Inheritance is therefore the mechanism where we will reuse the codes so as to accumulate the properties of a category into another class. Now we can say that we are more confident in types of inheritance in Java and become more familiar with Single Inheritance in Java, Multiple Inheritance, Multi-Level Inheritance, Hierarchical Inheritance, and Hybrid Inheritance.

We have talked about the differences between inheritance and subtyping. This can be achieved through the various sorts of inheritance patterns as shown within the article. However, there’s far more to the point of inheritance. I hope this blog helped you to understand all types of inheritance in Java.

Frequently Asked Question’s