{"id":10315,"date":"2025-08-14T11:30:32","date_gmt":"2025-08-14T11:30:32","guid":{"rendered":"https:\/\/www.kaashivinfotech.com\/blog\/?p=10315"},"modified":"2025-08-14T11:30:32","modified_gmt":"2025-08-14T11:30:32","slug":"oops-principles-in-java","status":"publish","type":"post","link":"https:\/\/www.kaashivinfotech.com\/blog\/oops-principles-in-java\/","title":{"rendered":"OOPS Principles in Java \u2013 Master Java Object Oriented Programming Concepts"},"content":{"rendered":"<p>The first thing you&#8217;ll learn, when you start taking Java classes, is the OOPS principles in Java. These principles are the foundation of <a href=\"https:\/\/www.wikitechy.com\/tutorials\/java\/\" target=\"_blank\" rel=\"noopener\">Java<\/a> object-oriented programming concepts.<\/p>\n<p>If you have a good understanding of them, you&#8217;ll be not coding \u2014 you&#8217;ll be building clean, reusable, scalable software like the pros do.<\/p>\n<h2><strong>What is OOPS in Java?<\/strong><\/h2>\n<ul>\n<li data-start=\"2351\" data-end=\"2515\">OOPS means <strong>Object-Oriented Programming System<\/strong>.<\/li>\n<li>In Java, OOP allows us to model real-world problems, with objects (things) and classes (the blueprint).<\/li>\n<li>Java is a pure <strong>OOP programming language<\/strong> because all of Java is based on classes and objects.<\/li>\n<\/ul>\n<h2><strong>The 4 Core OOPS Principles in Java<\/strong><\/h2>\n<figure id=\"attachment_10316\" aria-describedby=\"caption-attachment-10316\" style=\"width: 530px\" class=\"wp-caption aligncenter\"><img fetchpriority=\"high\" decoding=\"async\" class=\"wp-image-10316\" src=\"https:\/\/www.kaashivinfotech.com\/blog\/wp-content\/uploads\/2025\/08\/4-Core-OOPS-Principles-in-Java.webp\" alt=\"oops principles in java\" width=\"530\" height=\"391\" srcset=\"https:\/\/www.kaashivinfotech.com\/blog\/wp-content\/uploads\/2025\/08\/4-Core-OOPS-Principles-in-Java.webp 600w, https:\/\/www.kaashivinfotech.com\/blog\/wp-content\/uploads\/2025\/08\/4-Core-OOPS-Principles-in-Java-300x222.webp 300w, https:\/\/www.kaashivinfotech.com\/blog\/wp-content\/uploads\/2025\/08\/4-Core-OOPS-Principles-in-Java-380x281.webp 380w\" sizes=\"(max-width: 530px) 100vw, 530px\" \/><figcaption id=\"caption-attachment-10316\" class=\"wp-caption-text\">4 Core OOPS Principles in Java<\/figcaption><\/figure>\n<p data-start=\"2702\" data-end=\"2821\">When people talk about <strong data-start=\"2725\" data-end=\"2770\">Java object oriented programming concepts<\/strong>, they\u2019re usually referring to four main pillars:<\/p>\n<ol>\n<li data-start=\"2826\" data-end=\"2845\"><strong data-start=\"2826\" data-end=\"2843\">Encapsulation<\/strong><\/li>\n<li data-start=\"2849\" data-end=\"2866\"><strong data-start=\"2849\" data-end=\"2864\">Abstraction<\/strong><\/li>\n<li data-start=\"2870\" data-end=\"2887\"><strong data-start=\"2870\" data-end=\"2885\">Inheritance<\/strong><\/li>\n<li data-start=\"2891\" data-end=\"2909\"><strong data-start=\"2891\" data-end=\"2907\">Polymorphism<\/strong><\/li>\n<\/ol>\n<p data-start=\"2911\" data-end=\"2987\">Let\u2019s break these down one by one, with easy explanations and code examples.<\/p>\n<h3><strong>1. Encapsulation in Java<\/strong><\/h3>\n<p data-start=\"3028\" data-end=\"3153\"><strong data-start=\"3028\" data-end=\"3043\">Definition:<\/strong><br data-start=\"3043\" data-end=\"3046\" \/>Encapsulation is wrapping data (variables) and code (methods) together into a single unit.<\/p>\n<p>In Java, we achieve encapsulation by:<\/p>\n<ul>\n<li data-start=\"3197\" data-end=\"3230\">Declaring variables <strong data-start=\"3217\" data-end=\"3228\">private<\/strong><\/li>\n<li data-start=\"3233\" data-end=\"3288\">Providing <strong data-start=\"3243\" data-end=\"3273\">public getters and setters<\/strong> to access them<\/li>\n<\/ul>\n<p data-start=\"3290\" data-end=\"3302\"><strong data-start=\"3290\" data-end=\"3302\">Example:<\/strong><\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"java\">public class Student\r\n\r\n{\u00a0\u00a0\u00a0 private String name;\u00a0\u00a0\u00a0\u00a0\r\n\r\npublic String getName()\r\n\r\n{\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\r\n\r\nreturn name;\u00a0\u00a0\u00a0\r\n\r\n}\u00a0\u00a0\u00a0\u00a0\r\n\r\npublic void setName(String name)\r\n\r\n{\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\r\n\r\nthis.name = name;\u00a0\u00a0\u00a0\r\n\r\n}}<\/pre>\n<p data-start=\"3495\" data-end=\"3677\"><strong data-start=\"3495\" data-end=\"3517\">Real-life analogy:<\/strong> Think of <strong data-start=\"3527\" data-end=\"3551\">capsules in medicine<\/strong> \u2014 the medicine (data) is enclosed inside a protective shell (class), and you can only access it in controlled ways (methods).<\/p>\n<h3><strong>2. Abstraction in Java<\/strong><\/h3>\n<p data-start=\"3716\" data-end=\"3823\"><strong data-start=\"3716\" data-end=\"3731\">Definition:<\/strong><br data-start=\"3731\" data-end=\"3734\" \/>Abstraction means <strong>hiding implementation<\/strong>, and only showing functionality.<\/p>\n<p>We achieve abstraction in Java using:<\/p>\n<ul>\n<li data-start=\"3867\" data-end=\"3889\"><strong data-start=\"3867\" data-end=\"3887\">Abstract classes<\/strong><\/li>\n<li data-start=\"3892\" data-end=\"3906\"><strong data-start=\"3892\" data-end=\"3906\">Interfaces<\/strong><\/li>\n<\/ul>\n<p data-start=\"3908\" data-end=\"3920\"><strong data-start=\"3908\" data-end=\"3920\">Example:<\/strong><\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"java\">abstract class Vehicle\r\n\r\n{\u00a0\u00a0\u00a0\r\n\r\nabstract void start();\r\n\r\n}\u00a0\r\n\r\nclass Car extends Vehicle\r\n\r\n{\u00a0\u00a0\u00a0\r\n\r\nvoid start()\r\n\r\n{\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\r\n\r\nSystem.out.println(\"Car starts with a key.\");\u00a0\u00a0\u00a0\r\n\r\n}}<\/pre>\n<p data-start=\"4097\" data-end=\"4224\"><strong data-start=\"4097\" data-end=\"4119\">Real-life analogy:<\/strong> When you drive a car, you only know how to start it \u2014 you don\u2019t need to understand how the engine works.<\/p>\n<h3><strong>3. Inheritance in Java<\/strong><\/h3>\n<p data-start=\"4263\" data-end=\"4362\"><strong data-start=\"4263\" data-end=\"4278\">Definition:<\/strong><br data-start=\"4278\" data-end=\"4281\" \/>Inheritance allows one class to <strong>inherit properties and methods from another class<\/strong>.<\/p>\n<p>In Java, we use the extends keyword to implement inheritance in Java.<\/p>\n<p><strong>Example:<\/strong><\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"java\">class Animal\r\n\r\n{\u00a0\u00a0\u00a0\r\n\r\nvoid eat() {\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\r\n\r\nSystem.out.println(\"This animal eats food.\");\u00a0\u00a0\u00a0\r\n\r\n}}\u00a0\r\n\r\nclass Dog extends Animal\r\n\r\n{\u00a0\u00a0\u00a0 void bark()\r\n\r\n{\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\r\n\r\nSystem.out.println(\"Dog barks.\");\u00a0\u00a0\u00a0\r\n\r\n}}<\/pre>\n<p data-start=\"4643\" data-end=\"4768\"><strong data-start=\"4643\" data-end=\"4665\">Real-life analogy:<\/strong> Just like a child inherits traits from parents, a subclass inherits characteristics from a superclass.<\/p>\n<h3><strong>4. Polymorphism in Java<\/strong><\/h3>\n<p data-start=\"4808\" data-end=\"4938\"><strong data-start=\"4808\" data-end=\"4823\">Definition:<\/strong><br data-start=\"4823\" data-end=\"4826\" \/>Polymorphism means many forms. In Java, polymorphism allows the same method to behave differently depending on the object.<\/p>\n<p>Types:<\/p>\n<ul>\n<li><strong>Compile-time polymorphism<\/strong> (Method Overloading)<\/li>\n<li data-start=\"5006\" data-end=\"5050\"><strong data-start=\"5006\" data-end=\"5030\">Runtime polymorphism<\/strong> (Method Overriding)<\/li>\n<\/ul>\n<p data-start=\"5052\" data-end=\"5064\"><strong data-start=\"5052\" data-end=\"5064\">Example:<\/strong><\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"java\">class Calculator\r\n\r\n{\u00a0\u00a0\u00a0\r\n\r\nint add(int a, int b)\r\n\r\n{\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\r\n\r\nreturn a + b;\u00a0\u00a0\u00a0\r\n\r\n}\u00a0\u00a0\u00a0\u00a0\r\n\r\ndouble add(double a, double b)\r\n\r\n{\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\r\n\r\nreturn a + b;\u00a0\u00a0\u00a0\r\n\r\n}}<\/pre>\n<p data-start=\"5220\" data-end=\"5342\"><strong data-start=\"5220\" data-end=\"5242\">Real-life analogy:<\/strong> A single word like \u201crun\u201d can have different meanings \u2014 athletes run, programs run, and engines run.<\/p>\n<h2><strong>Why OOPS Principles in Java Matter<\/strong><\/h2>\n<p data-start=\"5392\" data-end=\"5470\">Understanding these <strong data-start=\"5412\" data-end=\"5457\">Java object oriented programming concepts<\/strong> helps you:<\/p>\n<ul>\n<li data-start=\"5473\" data-end=\"5494\">Write reusable code<\/li>\n<li data-start=\"5497\" data-end=\"5522\">Improve maintainability<\/li>\n<li data-start=\"5525\" data-end=\"5544\">Reduce redundancy<\/li>\n<li data-start=\"5547\" data-end=\"5574\">Build scalable applications<\/li>\n<\/ul>\n<h2><strong>Real-World Example of All OOP Principles Together<\/strong><\/h2>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"java\">abstract class Employee\r\n\r\n{\u00a0 \u00a0\r\n\r\nprivate String name; \/\/ Encapsulation\u00a0 \u00a0\r\n\r\n\u00a0public Employee(String name) {\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\r\n\r\nthis.name = name;\u00a0\u00a0\u00a0\r\n\r\n}\u00a0\u00a0\u00a0\u00a0\r\n\r\npublic abstract void work(); \/\/ Abstraction\u00a0\u00a0\u00a0\u00a0\r\n\r\npublic String getName() {\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\r\n\r\nreturn name;\u00a0\u00a0\u00a0\r\n\r\n}}\r\n\r\nclass Developer extends Employee {\u00a0\u00a0\u00a0\r\n\r\npublic Developer(String name) {\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\r\n\r\nsuper(name);\u00a0\u00a0\u00a0\r\n\r\n}\u00a0\u00a0\u00a0\u00a0\r\n\r\npublic void work() { \/\/ Polymorphism\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\r\n\r\nSystem.out.println(getName() + \" writes code.\");\u00a0\u00a0\u00a0\r\n\r\n}}\r\n\r\nclass Manager extends Employee {\u00a0\u00a0\u00a0\r\n\r\npublic Manager(String name) {\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\r\n\r\nsuper(name);\u00a0\u00a0\u00a0\r\n\r\n}\u00a0\u00a0\u00a0\u00a0\r\n\r\npublic void work() {\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\r\n\r\nSystem.out.println(getName() + \" manages the team.\");\u00a0\u00a0\u00a0\r\n\r\n}}\r\n\r\npublic class Company {\u00a0\u00a0\u00a0\r\n\r\npublic static void main(String[] args) {\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\r\n\r\nEmployee dev = new Developer(\"Alice\");\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\r\n\r\nEmployee mgr = new Manager(\"Bob\");\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\r\n\r\ndev.work();\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\r\n\r\nmgr.work();\u00a0\u00a0\u00a0\r\n\r\n}}<\/pre>\n<h2><strong>FAQs About OOPS Principles in Java<\/strong><\/h2>\n<p><strong>Q1<\/strong>: Is Java an Object Oriented Programming language?<\/p>\n<p>Not really &#8211; Java has primitives like int and char that are valuable data types but don&#8217;t classify as an object.<\/p>\n<p><strong>Q2<\/strong>: What is the most valuable OOPs concept?<\/p>\n<p>They are all valuable but encapsulation and abstraction give security and design to your code.<\/p>\n<p><strong>Q3<\/strong>: How do OOPs principles help you code?<\/p>\n<p>They make your code modular, maintainable, and reusable.<\/p>\n<h2><strong>Final Thoughts<\/strong><\/h2>\n<p data-start=\"155\" data-end=\"322\">If you genuinely would like to pursue your dream to be a java professional developer, then you can&#8217;t avoid learning &#8220;<strong>oops principles in java<\/strong>&#8221; and &#8220;<strong>java object oriented programming<\/strong>&#8220;.<\/p>\n<p>Oops principles in java are not just theories, but they are the real-world way of developing Java applications. Start implementing them in your java projects today, and you will be amazed at the difference in code quality, scalability and maintainability.<\/p>\n<p>If you want to increase your foundation of learning from starting to advanced, you might consider an organized <a href=\"https:\/\/www.kaashivinfotech.com\/java-course\/\"><strong>java course<\/strong><\/a>, that teaches everything from the basic parts of java to full stack and advanced java <strong>object oriented programming concepts<\/strong> with real projects. An organized and well-structured java development course will not only enhance your understanding of OOPS, but also prepares you for a job interview and working as a professional software development.<\/p>\n<h2>Related Links<\/h2>\n<ul>\n<li><a href=\"https:\/\/www.kaashivinfotech.com\/blog\/applications-of-oops\/\">Applications of OOPs \u2013 Real-World Use Cases of OOPS<\/a><\/li>\n<li><a href=\"https:\/\/www.kaashivinfotech.com\/blog\/how-to-run-a-java-program-in-cmd\/\">How to Run a Java Program in CMD: Step-by-Step Guide for Beginners<\/a><\/li>\n<li><a href=\"https:\/\/www.wikitechy.com\/what-are-the-different-types-of-java-control-statements\/\" target=\"_blank\" rel=\"noopener\">What are the different types of Java control statements ?<\/a><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>The first thing you&#8217;ll learn, when you start taking Java classes, is the OOPS principles in Java. These principles are the foundation of Java object-oriented programming concepts. If you have a good understanding of them, you&#8217;ll be not coding \u2014 you&#8217;ll be building clean, reusable, scalable software like the pros do. What is OOPS in [&hellip;]<\/p>\n","protected":false},"author":9,"featured_media":10318,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[8325,8324,8326,8328,8322,8323,8330,8329,8321,8327],"class_list":["post-10315","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-salaries","tag-abstraction-in-java","tag-encapsulation-in-java","tag-inheritance-in-java","tag-java-classes-and-objects","tag-java-object-oriented-programming-concepts","tag-java-oop-concepts","tag-java-programming-basics","tag-java-tutorial","tag-oops-principles-in-java","tag-polymorphism-in-java"],"_links":{"self":[{"href":"https:\/\/www.kaashivinfotech.com\/blog\/wp-json\/wp\/v2\/posts\/10315","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.kaashivinfotech.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.kaashivinfotech.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.kaashivinfotech.com\/blog\/wp-json\/wp\/v2\/users\/9"}],"replies":[{"embeddable":true,"href":"https:\/\/www.kaashivinfotech.com\/blog\/wp-json\/wp\/v2\/comments?post=10315"}],"version-history":[{"count":0,"href":"https:\/\/www.kaashivinfotech.com\/blog\/wp-json\/wp\/v2\/posts\/10315\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.kaashivinfotech.com\/blog\/wp-json\/wp\/v2\/media\/10318"}],"wp:attachment":[{"href":"https:\/\/www.kaashivinfotech.com\/blog\/wp-json\/wp\/v2\/media?parent=10315"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.kaashivinfotech.com\/blog\/wp-json\/wp\/v2\/categories?post=10315"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.kaashivinfotech.com\/blog\/wp-json\/wp\/v2\/tags?post=10315"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}