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Java - IntroductionJava - History of JavaJava - Features of Java

Java - Introduction

📌 What You Will Learn
  • What Java is and why it is so popular
  • The history and different versions of Java
  • The important features of Java
  • How Java is platform independent (Write Once, Run Anywhere)
  • The difference between JDK, JRE and JVM
  • How Java is different from C and C++

Introduction is a core concept of the Java language. This lesson explains What is Java? with complete, runnable code examples, clear step-by-step explanations, and common mistakes to avoid with exam-style MCQs at the end.

What is Java?

Java is a programming language and a platform. A programming language is a way to give instructions to the computer. Java gives us the rules and the tools to write those instructions.

Java was developed by James Gosling and his team at Sun Microsystems in the year 1991. It was first released to the public on 23 January 1996. Later, in the year 2010, the Oracle Corporation bought Sun Microsystems, so today Oracle owns and maintains Java.

Today Java is used almost everywhere — in banking applications, Android mobile apps, websites, school and college projects, and even in big company systems. That is why Java is one of the most popular languages for a fresh student to learn first.

Java has one special quality that makes it world famous: the same program can run on Windows, Linux, and Mac without any change. We call this platform independence.

In simple words: Platform independence means the same Java program runs on any operating system. You write the code once, and it works on Windows, Linux and Mac without any change.
Trainer's Note: Do not confuse Java and JavaScript. Java is a full programming language made by Sun Microsystems. JavaScript is a small scripting language used inside web browsers. They are two completely different languages.
📝 Key Takeaways
  • Java is a simple, secure, object-oriented programming language created by James Gosling at Sun Microsystems (now Oracle).
  • Write Once, Run Anywhere (WORA): source code (.java) is compiled to bytecode (.class), and every JVM runs that same bytecode.
  • JDK > JRE > JVM. JDK is for developers, JRE is for running, JVM executes bytecode.
  • Important versions: Java 8 (LTS), Java 11 (LTS), Java 17 (LTS), Java 21 (LTS).
  • Java is different from C/C++ because it has no pointers, automatic memory management, and is platform independent.

🧠 Test Your Knowledge

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