this and super Keywords in Java with Examples

this and super Keywords in Java with Examples | Noteshacker

Table of Content

Introduction:

In Java, “this” and “super” are keywords that serve different purposes but are related to object-oriented programming. This tutorial will provide a clear understanding of these two keywords, along with proper coding examples. By following the guidelines in this tutorial, you’ll be able to create SEO-friendly content that has a better chance of ranking in the top 10 Google searches.

Section 2: Understanding “this” Keyword

The “this” keyword in Java refers to the current instance of the class in which it is used. It is primarily used to differentiate between instance variables and method parameters or to invoke one constructor from another in the same class. Key points to understand about “this” are:

“this” can be used to refer to the instance variables, methods, or constructors of the current class.
It is particularly useful when you want to avoid naming conflicts between instance variables and method parameters.
It can be used to call other constructors in the same class, using the “this()” syntax.

Section 3: Explanation of “super” Keyword

The “super” keyword in Java is used to refer to the immediate parent class of a subclass. It allows you to access the superclass’s members (methods, variables, constructors) from the subclass. Important points to understand are:

“super” can be used to invoke the superclass’s constructor using the “super()” syntax. This is helpful when the subclass needs to initialize inherited fields or perform additional initialization steps.
It can also be used to call overridden methods in the superclass.
The keyword is particularly useful when you want to extend a class and customize its behavior without completely redefining it.

Section 4: Comparing “this” and “super”

While both “this” and “super” keywords are used in object-oriented programming, they have different purposes:

“this” refers to the current instance of the class, allowing access to its members.
“super” refers to the immediate parent class, enabling access to its members and constructors.

In summary, “this” is used for current class instance operations, while “super” is used to access the superclass’s elements.

Section 5: Coding Examples

In this section, we’ll provide coding examples to illustrate the usage of both “this” and “super” keywords.

5.1. Using “this”

public class ExampleClass {
    private int number;

    public ExampleClass(int number) {
        this.number = number;
    }

    public void setNumber(int number) {
        this.number = number;
    }
}

In the above example, “this. number” is used to distinguish between the instance variable and the method parameter, ensuring that the correct variable is assigned.

5.2. Using “super”

public class ParentClass {
    public ParentClass() {
        System.out.println("ParentClass constructor");
    }
}

public class ChildClass extends ParentClass {
    public ChildClass() {
        super(); // invoking the parent class constructor
        System.out.println("ChildClass constructor");
    }
}

The “super()” statement in the ChildClass constructor invokes the constructor of the ParentClass, allowing proper initialization of inherited fields.

Section 6: Conclusion

In this tutorial, we have explored the differences between the “this” and “super” keywords in Java. Understanding these keywords is crucial for effective object-oriented programming.

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