What are the main concepts of Java?

Have you wondered why you should learn Java? How can it kick-start your career in development and help you ace an interview for a good placement? Then you must opt for the Java Training in Bangalore to catch up on the most relevant programming skill. 

The Java Training will guide you through the core concepts of Java and make you career-ready.

Read on to know why you should learn Java and what are the core concepts of Java?

What is Java 

Java is an object-oriented language and computing platform first released by Sun Microsystems in 1995 that runs on billions of devices – notebook computers, mobile devices, gaming consoles, medical devices, and many others. Many software applications and devices will not function unless Java is installed. It is because Java is fast, secure, and reliable. Moreover, it is free to download. The rules and syntax of Java are based on the C and C++ languages, making it easy to learn and run.

When you download the Java software, you get the Java Runtime Environment (JRE) which consists of the Java Virtual Machine (JVM), Java platform core classes, and supporting Java platform libraries. The JRE is the runtime part of the Java software, which is all you need to run the same in your Web browser.

Java is different from JavaScript. Javascript does not need to be compiled, while Java code has to be compiled. Javascript only runs on web browsers while Java runs anywhere.

Why we need Java and why you must learn it

Java is one of the most popular programming languages used to create Web applications and platforms. It is known for its flexibility, allowing developers to write code that can run on any machine, regardless of architecture or platform.

Java has advantages over other languages and environments that make it suitable for just about any programming task. It is easy to use and learn, can be written, compiled, or debugged. Java is object-oriented and allows the creation of modular programs and reusable code. As it is platform-independent at both the source and binary levels, it allows running the same program on many different systems, which is critical for World Wide Web software. Because of the ease of use, cross-platform capabilities, and security features, Java has become the language of choice for worldwide Internet solutions.

Main concepts of Java

Java is the oldest programming language and continues to grow in its applicability. If you are new to Java, this brief introduction to the main concepts of Java and OOP can be your cheat sheet on your path to more efficient and effective coding. 

1. Abstraction or DRY

A key plus point of Java is the ability to reuse code and resources. However, we do not need repetition. The DRY (Don’t Repeat Yourself) principle means “don’t repeat yourself”. It is stated as “Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.” In Java, this means using interfaces and abstract classes to avoid repetition and hide internal implementation details. The consolidation makes for code that is easier to read and maintain. So the DRY principle says that if you need to write the same piece of code in many places, instead of copy-pasting it, make it a separate method and call that method wherever required. 

2. Polymorphism

Another OOP principle for reuse and efficiency is polymorphism which favors the use of a common interface. Polymorphism means having one thing take many forms, and in Java, it means that a single common interface is used for a general class of actions. The use of a common interface allows easier and faster integration of new requirements or features. Manual changes across the codebase are not required.

In Java, polymorphism is implemented with method overloading and method overriding. Method overloading takes place when various methods with the same name are present in a single class. The various methods may be differentiated by number, order, and types of their parameters. Method overriding takes place when a child’s class overrides the method of its parent.

3. Encapsulation

Data stored in fields within classes has to be protected from system-wide access, achieved through encapsulation, meaning a virtual capsule for data and code within the class itself. 

In Java, encapsulation is implemented by keeping class variables and methods private by default and providing access via public getter and setter methods. It helps to ease the testing and maintenance of code.

4. Inheritance

Inheritance is a feature of Object Oriented Programming (OOP) in Java. It allows the creation of new classes that share some of the attributes of existing classes. The concept enables building on previous work without reinventing the wheel.

5. Delegation

In Java, Delegation is an abstraction mechanism centralizing method behavior done manually through object composition.

Delegation allows a delegator object to unload tasks to a helper object. Delegation is a design principle that helps to cut down code duplication and modify behavior with ease.

6. Program to an interface, not an implementation

It is one of the most important design concepts in OOP in general and Java, in particular, to be applied in your code. 

Programming to interfaces is a way to write classes based on an interface that defines the behavior of the object. First, create an interface, then define its methods, and next write the actual class with the implementation.

This concept makes for flexible code and easy testing.

7. Single Responsibility Principle

The single responsibility principle (SRP) states that a class should only have one responsibility and only one cause to change. It prevents the output and functionality from being affected and the code from becoming a mess.

8. Open Closed Principle

The concept is that entities or objects should remain open for extension but remain closed for modification. 

In Java, this means that classes, methods, or functions should be open to allow the addition of functionality but closed to prevent the alteration of previously tested and functional code. 

9. Coupling

The concept of Coupling refers to the knowledge or dependency of another class. This occurs when classes are aware of each other. If a class has the details of another class, there is strong coupling. In Java, private, protected, and public modifiers are used to display the visibility level of a class, method, and field. Interfaces are used for weaker coupling as there is no concrete implementation.

10. Interface Segregation Principle

The Interface Segregation Principle (ISP) states that a client should not be forced to implement an interface that is not useable. Thus, larger interfaces should be split into smaller ones to ensure that implementing classes only factor relevant methods.

It reduces dependency complexity as the client is prevented from depending on what it doesn’t need.