{"id":10178,"date":"2024-09-21T14:27:40","date_gmt":"2024-09-21T14:27:40","guid":{"rendered":"https:\/\/stackify.com\/?p=10178"},"modified":"2024-10-17T14:28:57","modified_gmt":"2024-10-17T14:28:57","slug":"oops-concepts-in-java","status":"publish","type":"post","link":"https:\/\/stackify.com\/oops-concepts-in-java\/","title":{"rendered":"OOP Concepts in Java: Defined and Explained with Examples"},"content":{"rendered":"\n<p><i><span style=\"font-weight: 400;\">OOP is one of the most fundamental programming concepts. Let\u2019s explore the four main OOP concepts in Java and discuss how each works.<\/span><\/i><\/p>\n\n\n\n<p><span style=\"font-weight: 400;\">Java is one of <\/span><a href=\"https:\/\/stackify.com\/trendiest-programming-languages-hottest-sought-programming-languages-2017\/\"><span style=\"font-weight: 400;\">many programming languages<\/span><\/a><span style=\"font-weight: 400;\"> and technologies supported by Netreo\u2019s leading tools, <\/span><a href=\"https:\/\/stackify.com\/retrace\/\"><span style=\"font-weight: 400;\">Retrace<\/span><\/a><span style=\"font-weight: 400;\"> and <\/span><a href=\"https:\/\/stackify.com\/prefix\/\"><span style=\"font-weight: 400;\">Prefix<\/span><\/a><span style=\"font-weight: 400;\">. At Netreo, we aim to help developers become better. Let\u2019s take a look at some of the foundational Java programming language concepts with a primer on OOP concepts in Java.<\/span><\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"h-what-is-object-oriented-programming-oop\">What is Object Oriented Programming (OOP)?<\/h2>\n\n\n\n<p>Object Oriented Programming (OOP) is a programming paradigm that focuses on the use of objects to represent and manipulate data. In OOP, data is encapsulated within objects, and objects are defined by their properties (attributes) and behaviors (methods). OOP provides several key concepts that enable developers to write modular, reusable, and maintainable code.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"h-what-is-an-object\">What is an Object?<\/h2>\n\n\n\n<p>In the previous section, we&#8217;ve said that objects have properties and behavior, but we didn&#8217;t really define the concept. Let&#8217;s do it now.<\/p>\n\n\n\n<p>To explain what objects are, it&#8217;s probably a good idea to start by explaining what objects aren&#8217;t. So, programming languages that aren&#8217;t object oriented tend to have a stark separation between data and behavior. Basically, you have data represented by data structures, and behavior is implemented by functions that act on said data structures.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1000\" height=\"200\" src=\"https:\/\/stackify.com\/wp-content\/uploads\/2024\/09\/A-big-difference-between-OOP-and-non-OOP-is-that-an-object-should-expose-behavior-and-hide-most-or-all-of-its-data.png\" alt=\"A big difference between OOP and non-OOP is that an object should expose behavior and hide most or all of its data. \" class=\"wp-image-44713\" srcset=\"https:\/\/stackify.com\/wp-content\/uploads\/2024\/09\/A-big-difference-between-OOP-and-non-OOP-is-that-an-object-should-expose-behavior-and-hide-most-or-all-of-its-data.png 1000w, https:\/\/stackify.com\/wp-content\/uploads\/2024\/09\/A-big-difference-between-OOP-and-non-OOP-is-that-an-object-should-expose-behavior-and-hide-most-or-all-of-its-data-300x60.webp 300w, https:\/\/stackify.com\/wp-content\/uploads\/2024\/09\/A-big-difference-between-OOP-and-non-OOP-is-that-an-object-should-expose-behavior-and-hide-most-or-all-of-its-data-150x30.webp 150w, https:\/\/stackify.com\/wp-content\/uploads\/2024\/09\/A-big-difference-between-OOP-and-non-OOP-is-that-an-object-should-expose-behavior-and-hide-most-or-all-of-its-data-768x154.webp 768w, https:\/\/stackify.com\/wp-content\/uploads\/2024\/09\/A-big-difference-between-OOP-and-non-OOP-is-that-an-object-should-expose-behavior-and-hide-most-or-all-of-its-data-600x120.webp 600w\" sizes=\"(max-width: 1000px) 100vw, 1000px\" \/><\/figure>\n\n\n\n<p>An object is sort of a blend between the two, since it has both data and behavior. Each object represents an <strong>instance<\/strong> of a\u00a0certain domain concept or entity (e.g. a User, a Product, a Transaction), stores the data associated with that instance, and expose methods that potentially change that data.<\/p>\n\n\n\n<p>A big difference between OOP and non-OOP is that an object should expose behavior and hide most or all of its data. This is part of encapsulation, a key OOP concept we&#8217;ll cover in more detail next.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"h-definition-of-oop-concepts-in-java\">Definition of OOP Concepts in Java<\/h2>\n\n\n\n<p><span style=\"font-weight: 400;\">The main ideas behind Java\u2019s Object-Oriented Programming, OOP concepts include <\/span><a href=\"https:\/\/stackify.com\/oop-concept-abstraction\/\"><b>abstraction<\/b><\/a><b>, <\/b><a href=\"https:\/\/stackify.com\/oop-concept-for-beginners-what-is-encapsulation\/\"><b>encapsulation<\/b><\/a><span style=\"font-weight: 400;\">, <\/span><a href=\"https:\/\/stackify.com\/oop-concept-inheritance\/\"><b>inheritance<\/b><\/a><span style=\"font-weight: 400;\"> and<\/span><a href=\"https:\/\/stackify.com\/oop-concept-polymorphism\/\"><b> polymorphism<\/b><\/a><span style=\"font-weight: 400;\">. Basically, Java OOP concepts let us create working methods and variables, then re-use all or part of them without compromising security. Grasping OOP concepts is key to understanding how Java works.<\/span><\/p>\n\n\n\n<p>Java defines OOP concepts as follows:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><b>Abstraction.<\/b><span style=\"font-weight: 400;\"> Using simple things to represent complexity. We all know how to turn the TV on, but we don\u2019t need to know how it works in order to enjoy it. In Java, abstraction means simple things like <\/span><b>objects<\/b><span style=\"font-weight: 400;\">, <\/span><b>classes<\/b><span style=\"font-weight: 400;\"> and <\/span><b>variables<\/b><span style=\"font-weight: 400;\"> represent more complex underlying code and data. This is important because it lets you avoid repeating the same work multiple times.<\/span><\/li>\n\n\n\n<li><b>Encapsulation. <\/b><span style=\"font-weight: 400;\">The practice of keeping fields within a class private, then providing access to those fields via public methods. Encapsulation is a protective barrier that keeps the data and code safe within the class itself. We can then reuse objects like code components or variables without allowing open access to the data system-wide.<\/span><\/li>\n\n\n\n<li><b>Inheritance. <\/b><span style=\"font-weight: 400;\">A special feature of Object-Oriented Programming in Java, Inheritance lets programmers create new classes that share some of the attributes of existing classes. Using Inheritance lets us build on previous work without reinventing the wheel.<\/span><\/li>\n\n\n\n<li><b>Polymorphism. <\/b><span style=\"font-weight: 400;\">Allows programmers to use the same word in Java to mean different things in different contexts. One form of polymorphism is <\/span><b>method overloading<\/b><span style=\"font-weight: 400;\">. That\u2019s when the code itself implies different meanings. The other form is <\/span><b>method overriding<\/b><span style=\"font-weight: 400;\">. That\u2019s when the values of the supplied variables imply different meanings. Let\u2019s delve a little further.<\/span><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"h-how-oop-concepts-in-java-work\">How OOP Concepts in Java Work<\/h2>\n\n\n\n<p>OOP concepts in Java work by letting programmers create components that are reusable in different ways while maintaining security.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-how-abstraction-works\">How Abstraction Works<\/h3>\n\n\n\n<p>Abstraction lets programmers create useful and reusable tools. It enables programmers to create complex systems by breaking them down into smaller, more manageable components. For example, a programmer can create several different types of <strong>objects<\/strong>, which can be variables, functions or data structures. Programmers can also create different&nbsp;<strong>classes<\/strong> of objects as ways to define the objects.<\/p>\n\n\n\n<p>For instance, a class of variable might be an address. The class might specify that each address object shall have a name, street, city and zip code. The objects, in this case, might be employee addresses, customer addresses or supplier addresses. In addition, abstraction provides a mechanism for hiding the implementation details of a class or method from the outside world and providing a simplified interface for clients to interact with. In Java, you can achieve abstraction through two main mechanisms: abstract classes and interfaces.<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Abstract Classes:<\/strong> An abstract class is a class that you can&#8217;t instantiate and can only extend by subclasses. Abstract classes can have both abstract and non-abstract methods. Abstract methods do not have a body and you must implement them by any subclass that extends the abstract class. Non-abstract methods have a body and you can directly call them by the subclass.<\/li>\n\n\n\n<li><strong>Interfaces:<\/strong> An interface is a collection of methods. You can use it to define a set of behaviors that a class should implement. A class can implement multiple interfaces, and all the methods defined in an interface must be implemented by any class that implements it.<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-how-encapsulation-works\">How Encapsulation Works<\/h3>\n\n\n\n<p>Encapsulation lets us reuse functionality without jeopardizing security. It\u2019s a powerful, time-saving OOP concept in Java. For example, we may create a piece of code that calls specific data from a database. It may be useful to reuse that code with other databases or processes. Encapsulation lets us do that while keeping our original data private. It also lets us alter our original code without breaking it for others who have adopted it in the meantime.<\/p>\n\n\n\n<p>Encapsulation provides several benefits, including:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Data hiding:<\/strong> By hiding the implementation details of a class, encapsulation protects the data from unauthorized access and manipulation.<\/li>\n\n\n\n<li><strong>Modularity:<\/strong> Encapsulation helps to break down complex systems into smaller, more manageable components, making the codebase more modular and easier to maintain.<\/li>\n\n\n\n<li><strong>Flexibility:<\/strong> By providing a controlled interface for interacting with a class, encapsulation allows for changes to the internal implementation without affecting the external interface.<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-access-modifiers\">Access Modifiers<\/h3>\n\n\n\n<p>In Java, encapsulation is implemented using access modifiers, which control the visibility of variables and methods within a class.<\/p>\n\n\n\n<p>The three access modifiers in Java are:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Public:<\/strong> Public variables and methods can be accessed from anywhere, including outside the class.<\/li>\n\n\n\n<li><strong>Private:<\/strong> Private variables and methods can only be accessed within the class they are defined in.<\/li>\n\n\n\n<li><strong>Protected:<\/strong> Protected variables and methods can be accessed within the same class and its subclasses.<\/li>\n<\/ol>\n\n\n\n<p>Encapsulation enables developers to write cleaner, more organized, and more secure code. By controlling access to variables and methods, encapsulation promotes good software design practices and helps to manage the complexity of large-scale projects.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-how-inheritance-works\">How Inheritance Works<\/h3>\n\n\n\n<p>Inheritance is another labor-saving Java OOP concept that works by letting a new class adopt the properties of another. We call the inheriting class a&nbsp;<strong>subclass<\/strong>&nbsp;or a&nbsp;<strong>child class<\/strong>. The original class is often called the&nbsp;<strong>parent <\/strong>or the <strong>superclass<\/strong>. We use the keyword&nbsp;<strong>extends<\/strong>&nbsp;to define a new class that inherits properties from an old class.<\/p>\n\n\n\n<p>The subclass inherits all the public and protected variables and methods of the superclass, and it can also define its own variables and methods. This makes it possible to create a hierarchy of classes, where each subclass inherits from its superclass and adds its own unique features.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-benefits-of-inheritance\">Benefits of Inheritance<\/h3>\n\n\n\n<p>Inheritance provides several benefits, including:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Reusability:<\/strong> By inheriting from a superclass, a subclass can reuse the code and functionality already defined in the superclass, making it easier to write and maintain code.<\/li>\n\n\n\n<li><strong>Polymorphism:<\/strong> Inheritance allows for polymorphism, where objects of different subclasses can be treated as objects of the same superclass, making it easier to write generic code.<\/li>\n\n\n\n<li><strong>Flexibility:<\/strong> Inheritance provides a way to add new features to an existing class hierarchy without modifying the existing code.<\/li>\n<\/ol>\n\n\n\n<p>Inheritance allows developers to create complex class hierarchies with shared functionality and unique features. By promoting code reuse, polymorphism, and flexibility, inheritance enables developers to write more efficient and maintainable code.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-how-polymorphism-works\">How Polymorphism Works<\/h3>\n\n\n\n<p>Polymorphism in Java works by using a reference to a parent class to affect an object in the child class. We might create a class called \u201chorse\u201d by extending the \u201canimal\u201d class. That class might also implement the \u201cprofessional racing\u201d class. The \u201chorse\u201d class is \u201cpolymorphic,\u201d since it inherits attributes of both the \u201canimal\u201d and \u201cprofessional racing\u201d class.<\/p>\n\n\n\n<p>Two more examples of polymorphism in Java are method overriding and method overloading.<\/p>\n\n\n\n<p>In&nbsp;<strong>method<\/strong>&nbsp;<strong>overriding<\/strong>, the child class can use the OOP polymorphism concept to override a method of its parent class. That allows a programmer to use one method in different ways depending on whether it\u2019s invoked by an object of the parent class or an object of the child class.<\/p>\n\n\n\n<p>In&nbsp;<strong>method overloading,&nbsp;<\/strong>a single method may perform different functions depending on the context in which it\u2019s called. This means a single method name might work in different ways depending on what arguments are passed to it.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-benefits-of-polymorphism\">Benefits of Polymorphism<\/h3>\n\n\n\n<p>Polymorphism provides several benefits, including:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Flexibility:<\/strong> Polymorphism allows for more flexible and adaptable code by enabling objects of different classes to be treated as if they are of the same class.<\/li>\n\n\n\n<li><strong>Code reuse:<\/strong> Polymorphism promotes code reuse by allowing classes to inherit functionality from other classes and to share common methods and properties.<\/li>\n\n\n\n<li><strong>Simplification:<\/strong> Polymorphism simplifies code by enabling the use of generic code that can handle different types of objects.<\/li>\n<\/ol>\n\n\n\n<p>Polymorphism allows for more flexible and adaptable code. By enabling objects of different classes to be treated as if they are of the same class, polymorphism promotes code reuse, simplification, and flexibility, making it an essential component of Object-Oriented Programming.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"h-examples-of-oop-concepts-in-java\">Examples of OOP Concepts in Java<\/h2>\n\n\n\n<p><span style=\"font-weight: 400;\">Now that we explained the foundational OOP concepts in Java, let\u2019s look at a few common examples.<\/span><\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-short-encapsulation-example-in-java\">Short Encapsulation Example in Java<\/h3>\n\n\n\n<p><span style=\"font-weight: 400;\">In the example below, <\/span><a href=\"https:\/\/www.javatpoint.com\/encapsulation\"><span style=\"font-weight: 400;\">encapsulation<\/span><\/a><span style=\"font-weight: 400;\"> is demonstrated as an OOP concept in Java. Here, the variable \u201cname\u201d is kept private or \u201cencapsulated.\u201d<\/span><\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">\/\/save as Student.java\npackage com.javatpoint;\npublic class Student {\n private String name;\n public String getName() {\n  return name;\n }\n public void setName(String name) {\n  this.name = name\n }\n}\n\/\/save as Test.java\npackage com.javatpoint;\nclass Test {\n public static void main(String[] args) {\n  Student s = new Student();\n  s.setName(\u201cvijay\u201d);\n  System.out.println(s.getName());\n }\n}<\/pre>\n\n\n\n<pre class=\"wp-block-preformatted\">Compile By: javac -d . Test.java\nRun By: java com.javatpoint.Test\n\nOutput: vijay<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-example-of-inheritance-in-java\">Example of Inheritance in Java<\/h3>\n\n\n\n<p><span style=\"font-weight: 400;\">It\u2019s quite simple to achieve inheritance as an OOP concept in Java. Inheritance can be as easy as using the <\/span><b>extends<\/b><span style=\"font-weight: 400;\"> keyword:<\/span><\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">class Mammal {\n\n}\nclass Aardvark extends Mammal {\n\n}\n<\/pre>\n\n\n\n<p><span style=\"font-weight: 400;\">For a full tutorial on the different ways to use inheritance in java, <\/span><a href=\"https:\/\/www.tutorialspoint.com\/java\/java_inheritance.htm\"><span style=\"font-weight: 400;\">see this blog post<\/span><\/a><span style=\"font-weight: 400;\">.<\/span><\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-short-example-of-polymorphism-in-java\">Short Example of Polymorphism in Java<\/h3>\n\n\n\n<p><span style=\"font-weight: 400;\">In the example below of polymorphism as an OOP concept in Java, we have two classes: Person and Employee. The Employee class inherits from the Person class by using the keyword <\/span><b>extends<\/b><span style=\"font-weight: 400;\">. Here, the child class overrides the parent class. For the full example, <\/span><a href=\"http:\/\/www.sitesbay.com\/java\/java-polymorphism\"><span style=\"font-weight: 400;\">see this blog post<\/span><\/a><span style=\"font-weight: 400;\">.<\/span><\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">class Person {\n void walk() {\n  System.out.println(\u201cCan Run\u2026.\u201d);\n }\n}\nclass Employee extends Person {\n void walk() {\n  System.out.println(\u201cRunning Fast\u2026\u201d);\n }\n public static void main(String arg[]) {\n  Person p = new Employee(); \/\/upcasting\n  p.walk();\n }\n}\n<\/pre>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"h-differences-between-oop-and-other-programming-styles\">Differences between OOP and other programming styles<\/h2>\n\n\n\n<p>Object-Oriented Programming (OOP) has become widely popular due to its many advantages over other programming styles such as Procedural Programming and Functional Programming.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-procedural-programming\">Procedural Programming<\/h3>\n\n\n\n<p><strong>Procedural Programming<\/strong> is a programming style that is based on a set of procedures or functions, where each function is a sequence of instructions that performs a specific task. It focuses on the sequence of must-follow steps that to accomplish a specific task. In contrast, OOP focuses on the objects and their interactions to solve problems.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-functional-programming\">Functional Programming<\/h3>\n\n\n\n<p><strong>Functional Programming<\/strong> is a programming style that focuses on the use of functions that produce output based on their input, without modifying any external state. It is based on mathematical functions and is characterized by immutability and statelessness. In contrast, OOP is based on objects and their states, and it is designed to manage complex, stateful systems.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"h-benefits-of-oop-over-other-programming\">Benefits of OOP over other programming<\/h3>\n\n\n\n<p>Here are some key differences between OOP and other programming styles:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Data and behavior:<\/strong> OOP is based on the idea of encapsulating data and behavior within objects, whereas procedural programming separates data and behavior into different functions or procedures. Functional programming, on the other hand, treats data and behavior as separate entities altogether.<\/li>\n\n\n\n<li><strong>Inheritance and code reuse:<\/strong> OOP uses inheritance to reuse code and build complex systems. Procedural programming and functional programming do not have inheritance concepts built into them.<\/li>\n\n\n\n<li><strong>Flexibility:<\/strong> OOP is more flexible than procedural programming because it allows for changes to be made to the underlying data structures and objects without changing the entire system. In contrast, procedural programming requires a complete restructuring of the program if any changes are made.<\/li>\n<\/ol>\n\n\n\n<p>OOP enables encapsulation, inheritance, code reusability, and flexibility, making it a powerful tool for building complex, stateful systems.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Java Packages: What Are They?<\/h2>\n\n\n\n<p>Java packages aren&#8217;t really an OOP concept per se, but it is essential in Java programming, so we&#8217;ve figured it&#8217;d make sense to cover it briefly.<\/p>\n\n\n\n<p>In any medium-sized to large application, you&#8217;ll probably end-up with many, many classes. It&#8217;s useful to keep classes that represent similar concepts together, while keeping the different ones apart. In other words, it&#8217;s beneficial to have some kind of grouping ability when it comes to classes.<\/p>\n\n\n\n<p>That&#8217;s exactly where packages come in handy. Packages allow you to organize your classes, grouping them by functionality, hierarchy, and separation of concerns. Java packages also solve the problem of naming conflicts: you can have as many classes with the same name as you&#8217;d like, as long as they belong to different packages.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1000\" height=\"200\" src=\"https:\/\/stackify.com\/wp-content\/uploads\/2024\/09\/Packages-allow-you-to-organize-your-classes-grouping-them-by-functionality-hierarchy-and-separation-of-concerns.png\" alt=\"Packages allow you to organize your classes, grouping them by functionality, hierarchy, and separation of concerns.\" class=\"wp-image-44714\" style=\"width:840px;height:auto\" srcset=\"https:\/\/stackify.com\/wp-content\/uploads\/2024\/09\/Packages-allow-you-to-organize-your-classes-grouping-them-by-functionality-hierarchy-and-separation-of-concerns.png 1000w, https:\/\/stackify.com\/wp-content\/uploads\/2024\/09\/Packages-allow-you-to-organize-your-classes-grouping-them-by-functionality-hierarchy-and-separation-of-concerns-300x60.webp 300w, https:\/\/stackify.com\/wp-content\/uploads\/2024\/09\/Packages-allow-you-to-organize-your-classes-grouping-them-by-functionality-hierarchy-and-separation-of-concerns-150x30.webp 150w, https:\/\/stackify.com\/wp-content\/uploads\/2024\/09\/Packages-allow-you-to-organize-your-classes-grouping-them-by-functionality-hierarchy-and-separation-of-concerns-768x154.webp 768w, https:\/\/stackify.com\/wp-content\/uploads\/2024\/09\/Packages-allow-you-to-organize-your-classes-grouping-them-by-functionality-hierarchy-and-separation-of-concerns-600x120.webp 600w\" sizes=\"(max-width: 1000px) 100vw, 1000px\" \/><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"h-best-practices-for-oop-concepts-in-java\">Best Practices for OOP Concepts in Java<\/h2>\n\n\n\n<p><span style=\"font-weight: 400;\">The goal of OOP concepts in Java is to save time without sacrificing security and ease of use. The following best practices are all oriented toward advancing that main goal.<\/span><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><b>DRY (Don\u2019t Repeat Yourself). <\/b><span style=\"font-weight: 400;\">A core concept in Java, DRY simply means you should never have two blocks of identical code in two different places. Instead, have one method you use for different applications.<\/span><\/li>\n\n\n\n<li><span style=\"font-weight: 400;\">If you expect your Java code to change in the future, encapsulate it by making all variables and methods private at the outset. As the code changes, increase access to <\/span><b>\u201cprotected\u201d <\/b><span style=\"font-weight: 400;\">as needed, but not too <\/span><b>public.<\/b><\/li>\n\n\n\n<li><b>Single Responsibility. <\/b><span style=\"font-weight: 400;\">This best practice principle for OOP concepts in Java states that a class should always have only one functionality. That way, the class can be called and\/or extended on its own when new uses arise for it, without causing <\/span><b>coupling<\/b><span style=\"font-weight: 400;\"> between different functionalities.<\/span><\/li>\n\n\n\n<li><span style=\"font-weight: 400;\"><b>Open Closed Design. <\/b>Make all methods and classes Closed for modification but Open for an extension. That way, tried and tested code can remain static but can be modified to perform new tasks as needed.<\/span><\/li>\n<\/ul>\n\n\n\n<p><span style=\"font-weight: 400;\">For a good, full list of best practices for OOP concepts in Java, <\/span><a href=\"https:\/\/javarevisited.blogspot.com\/2012\/03\/10-object-oriented-design-principles.html\"><span style=\"font-weight: 400;\">see this blog post<\/span><\/a><span style=\"font-weight: 400;\">. You can also check out our article about <\/span><a href=\"https:\/\/stackify.com\/oop-concepts-c-sharp\/\"><span style=\"font-weight: 400;\">OOP concepts in C#<\/span><\/a><span style=\"font-weight: 400;\">.<\/span><\/p>\n\n\n\n<p><span style=\"font-weight: 400;\">These concepts and best practices are only as great as the developers that implement them. To make your work better, you need productivity tools to improve your Java programming.<\/span><\/p>\n\n\n\n<p><span style=\"font-weight: 400;\">Try Netreo\u2019s <\/span><a href=\"https:\/\/stackify.com\/prefix\/\"><span style=\"font-weight: 400;\">Prefix<\/span><\/a><span style=\"font-weight: 400;\"> and <\/span><a href=\"https:\/\/stackify.com\/retrace\/\"><span style=\"font-weight: 400;\">Retrace <\/span><\/a><span style=\"font-weight: 400;\">to help you write and maintain the best code ever!<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>OOP Concepts (Object Oriented Programming) are key to understanding Java. Learn about abstraction, encapsulation, inheritance, and polymorphism.<\/p>\n","protected":false},"author":14,"featured_media":44936,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[7],"tags":[52],"class_list":["post-10178","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-developers","tag-developer-tips"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v25.6 (Yoast SEO v25.6) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>What Are OOP Concepts in Java?<\/title>\n<meta name=\"description\" content=\"Today we&#039;ll discuss OOP Concepts (Object Oriented Programming), the key to understanding Java. 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