When is `super()` Really Necessary in a Constructor?
Super() in Constructor: A Question of Necessity
In the realm of object-oriented programming, constructors play a crucial role in initializing newly created objects. However, the question arises: is it essential to explicitly call the super() method within a subclass's constructor?
Automatic Invocation
In the absence of an explicit super() call, the compiler automatically invokes the accessible no-args constructor in the superclass. This constructor has no parameters and is vital for properly initializing the superclass's instance members.
Constructors with Arguments
When a subclass's constructor includes arguments, it typically delegates initialization tasks to a constructor in the superclass with a matching argument list. If no matching constructor is found, an error occurs. In other words, the constructor invoked via super() must have arguments that exactly match the arguments passed to the subclass's constructor.
Importance of Accessibility
The accessible no-args constructor in the superclass must be visible to the subclass. If the superclass constructor is private or protected, an explicit call to super() with appropriate arguments is necessary to invoke the correct constructor.
Examples
To illustrate these concepts, consider the following code snippets:
1 |
|
In this case, the default constructor in Base will be automatically invoked when an instance of Derived is created.
1 |
|
Here, the constructor in Derived explicitly invokes the matching constructor in Base with the argument i.
1 |
|
This code results in an error because Base's constructor is private and not accessible to the subclass.
In conclusion, while the compiler automatically invokes the accessible no-args constructor in the superclass, explicit super() calls are essential when a subclass's constructor has arguments or when the superclass's constructor is not accessible. Understanding these nuances is crucial for ensuring proper object initialization in Java.
The above is the detailed content of When is `super()` Really Necessary in a Constructor?. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics











Troubleshooting and solutions to the company's security software that causes some applications to not function properly. Many companies will deploy security software in order to ensure internal network security. ...

Solutions to convert names to numbers to implement sorting In many application scenarios, users may need to sort in groups, especially in one...

Field mapping processing in system docking often encounters a difficult problem when performing system docking: how to effectively map the interface fields of system A...

When using MyBatis-Plus or other ORM frameworks for database operations, it is often necessary to construct query conditions based on the attribute name of the entity class. If you manually every time...

Start Spring using IntelliJIDEAUltimate version...

Conversion of Java Objects and Arrays: In-depth discussion of the risks and correct methods of cast type conversion Many Java beginners will encounter the conversion of an object into an array...

Detailed explanation of the design of SKU and SPU tables on e-commerce platforms This article will discuss the database design issues of SKU and SPU in e-commerce platforms, especially how to deal with user-defined sales...

How does the Redis caching solution realize the requirements of product ranking list? During the development process, we often need to deal with the requirements of rankings, such as displaying a...
