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#SUPER CONSTRUCTOR JAVA SOFTWARE#

In the next tutorial, we will discuss another keyword ‘implements’ using which we can inherit interfaces. The inheritance implemented with the ‘extends’ keyword is the class inheritance. In other words, the extends keyword indicates that we are building a new class SubClass on the existing functionality of the SuperClass. The keyword ‘extends’ conveys that we are creating a new class ‘SubClass’ that will inherit the properties and behavior from ‘SuperClass’. The general syntax of Java inheritance is given below: class SubClass extends SuperClassĪs shown above, the ‘extends’ keyword appears after the classname in the class declaration syntax. In Java, the keyword ‘extends’ is used to inherit the class. The class SoftwareDeveloper class inherits from the Employee class, and hence it also acquires the properties of the Employee class.Īs shown in the above diagram, here Employee class is a Super or Base class and SoftwareDeveloper is a subclass or derived class. Then we derive another class named ‘SoftwareDeveloper” with the field’s salary and perks. In your case, it is necessary because the call to super() cannot be placed automatically due to the fact that Employee's constructor has parameters. It can also have other fields like Employee name, department, and other employee details. In order to accomplish that, Java automatically puts a super() call in each constructor's first line, you can put it manually but usually it is not necessary. We have an Employee class with fields OrganisationName and EmployeeId.

The following inheritance hierarchy is an example showing a superclass and subclass.

Super Class/Parent Class: A class that is inherited by another class to acquire properties and methods is called a Parent class or superclass or a base class.

Sub Class/Child Class: A class that inherits from another class is a subclass or a child class or a derived class.

A class can be viewed as a template or a blueprint for the objects.

Class: A class is a collection of objects that have common properties.

Reusability: Mechanism by which new classes reuse fields or properties and methods of an existing class.

By inheriting from the already existing classes, we ensure the reusability of code.

For method overriding so that we can achieve Read Through The Easy Java Training Series.

The class from which the new class is inherited is called the “ Parent class” while the new class is called the “ Child class”. The inheritance feature depicts a “ parent-child” connection or relationship in Java. Besides, we can add more properties and/or behavior to our new class. By inheriting from the already existing classes, we get to use the properties and behavior of these classes. So a general idea behind the feature “Inheritance” is that we can create new classes by inheriting from the already existing classes. We will directly create a class each for amphibian animals and inherit from the Amphibian class as shown below. This way we do not have to duplicate the common properties and behavior of every amphibian animal we describe.

#SUPER CONSTRUCTOR JAVA SOFTWARE#

If we have to represent the amphibian species and its members in a software representation using OOP, then what we will do is we will develop a class “Amphibian” containing properties or behavior that is common to amphibians in general. But programmers can also call another constructor explicitly using the keywords this () or super (). This happens implicitly when a subclass is constructed: its first task is to call its parents constructor method. So here an Amphibian is a species and animals like frogs are its members. Constructor chaining in Java is simply the act of one constructor calling another constructor via inheritance. Like other animals of the Amphibian class, Frog might have many characteristics that are common to other animals. This is done by inheriting the class or establishing a relationship between two classes.įor example, a Frog is an amphibian. So when you need to perform a constructor chaining or call the superclass constructor, make sure that you do it on the first line.Inheritance in Java can be defined as a technique or process in which one object of a class acquires the behavior and properties of another object. It’s a rule set up by Java itself to prevent errors by disabling dynamic orders between the initialization of the class object and other assignments and operations. When other statements before the super() constructor are allowed, then you might try to call or manipulate class members and methods that are not yet constructed.

You need to call the super() constructor before anything else. The same happens when you extend a superclass.

This is because when you run other statements before the call to the constructor, then you might call some methods or states that are not yet defined.