Java Introduction

What is Java? Introduction, History, Features & Latest JDK Versions

Java is one of the most widely used programming languages in the world, powering everything from Android apps to enterprise backends and big-data systems. In this beginner-friendly introduction, you will learn what Java is, its history, the WORA concept, its top features, and the latest JDK versions you should use in 2026.

Whether you are just starting your programming journey or switching from another language, this guide gives you a complete foundation.

Table of Contents

• What is Java?
• Where is Java Used?
• History of Java
• Why Java Was Invented (WORA)
• Java / JDK Versions (Latest in 2026)
• Features of Java
• Frequently Asked Questions
• Conclusion

What is Java?

Java is a general-purpose, object-oriented, high-level programming language used to build desktop, web, mobile, and enterprise applications.

Java is a third-generation language that uses both a compiler and an interpreter. Source code is compiled into bytecode, and the Java Virtual Machine (JVM) interprets that bytecode on the target platform.

Java is owned by Oracle Corporation and follows a predictable release schedule with a new version every six months and a Long-Term Support (LTS) release every two years.

Where is Java Used?

Java is used in different areas, but primarily in these three:

1. Desktop Applications — standalone software such as IDEs and utilities.
2. Web Applications — server-side systems built with Spring Boot, Servlets, JSP, and REST APIs.
3. Mobile Applications — Android apps (Kotlin is now preferred, but Java is still widely supported).

Beyond these, Java is also used in big data (Hadoop, Spark), cloud computing, embedded systems, and scientific applications.

History of Java

Java was created in 1991 by a team led by James Gosling at Sun Microsystems. It was originally named Oak as part of the Green Project, with file extensions like .gt (Green Talk).

Due to a trademark conflict, the language was renamed Java in 1995. In 2010, Oracle Corporation acquired Sun Microsystems, and Java has been a product of Oracle ever since.

Java has maintained a strong commitment to backward compatibility, meaning code written for older versions usually continues to run on newer versions.

Why Java Was Invented (WORA)

Java was invented to solve a common problem: code written for one operating system would not run on another. The goal was to achieve the WORA principle:

WORA = Write Once, Run Anywhere

With Java, a developer compiles the source code once into bytecode, and that bytecode can be executed on any platform that has a Java Virtual Machine (JVM) — Windows, macOS, Linux, or embedded systems.

This platform independence is the single most important reason Java became so popular for enterprise and cross-platform development.

Java / JDK Versions (Latest in 2026)

Java follows a six-month release cycle since Java 9, with a new feature release every March and September. Every two years, one release is designated as LTS (Long-Term Support) — these are the versions recommended for production use.

Current LTS versions (recommended for production):

• Java 25 LTS — Released September 2025. Latest LTS. Adds Scoped Values, Module Import Declarations, Flexible Constructor Bodies, and more. Supported until September 2033.
• Java 21 LTS — Released September 2023. Introduced Virtual Threads, Pattern Matching for switch, and Record Patterns. Supported until September 2031.
• Java 17 LTS — Released September 2021. Introduced Sealed Classes, Records, and Text Blocks. Supported until September 2029.
• Java 11 LTS — Released September 2018. Introduced the HTTP Client API and Lambda local variables. Supported until January 2032.
• Java 8 LTS — Released March 2014. Introduced Lambdas and Streams. Still widely used; commercial support extends to December 2030.

Latest non-LTS feature release:

• Java 26 — Released March 2026. Adds HTTP/3 support in the HTTP Client API and removes the Applet API. Non-LTS; use for testing and experimentation only.

Recommendation for 2026: Use Java 25 LTS for new production projects. Use Java 21 LTS if your dependencies have not yet been tested with 25. Use Java 8 only for legacy systems.

Full JDK version history:

1. JDK 1.0 — January 23, 1996
2. JDK 1.1 — February 19, 1997
3. J2SE 1.2 — December 4, 1998
4. J2SE 1.3 — May 8, 2000
5. J2SE 1.4 — February 13, 2002
6. J2SE 5.0 — September 30, 2004
7. Java SE 6 — December 11, 2006
8. Java SE 7 — July 28, 2011
9. Java SE 8 (LTS) — March 18, 2014
10. Java SE 9 — September 21, 2017
11. Java SE 10 — March 20, 2018
12. Java SE 11 (LTS) — September 25, 2018
13. Java SE 12 — March 19, 2019
14. Java SE 13 — September 17, 2019
15. Java SE 14 — March 17, 2020
16. Java SE 15 — September 15, 2020
17. Java SE 16 — March 16, 2021
18. Java SE 17 (LTS) — September 14, 2021
19. Java SE 18 — March 22, 2022
20. Java SE 19 — September 20, 2022
21. Java SE 20 — March 21, 2023
22. Java SE 21 (LTS) — September 19, 2023
23. Java SE 22 — March 19, 2024
24. Java SE 23 — September 17, 2024
25. Java SE 24 — March 18, 2025
26. Java SE 25 (LTS) — September 16, 2025
27. Java SE 26 — March 17, 2026

Source: Oracle Java SE release history and specifications.

Features of Java

Java has the following features:

1. Simple
2. Robust
3. Platform Independent
4. Dynamic
5. Interpreter-Based
6. Secure
7. Architecture Neutral
8. Distributed
9. Multithreaded
10. Open Source
11. API-Based
12. Portable
13. High Performance
14. Object-Oriented

Simple

• Java's syntax is borrowed from C and C++, making it familiar to many developers.
• It does not have destructors, explicit pointers, or operator overloading.
• It supports call by value only and provides a rich built-in API.
• It does not support multiple inheritance of classes, avoiding ambiguity.

Robust

• Automatic garbage collection removes objects that are no longer used.
• Developers do not need to worry about manual memory management.
• Strong exception handling and type checking at compile time and runtime.

Platform Independent

• Source code compiles to .class bytecode using javac.
• Bytecode runs on any platform that has a JVM.
• This is the "Write Once, Run Anywhere" principle.

Dynamic

• Classes are loaded at runtime into the JVM.
• Memory is allocated at runtime when classes are loaded.

Interpreter-Based

• Java uses both a compiler (javac) and an interpreter (JVM).
• The JVM interprets bytecode into native machine code for the host platform.
• Each platform has its own JVM implementation.

Secure

• No explicit pointers, so memory addresses cannot be accessed without authorization.
• The Byte Code Verifier checks class code at runtime.
• The Sandbox security model restricts access to system resources.

Architecture Neutral

• Primitive data type sizes are fixed across all architectures (32-bit or 64-bit).
• No need to change hardware or software to run on different platforms.

Distributed

• Java supports distributed computing across networks.
• RMI (Remote Method Invocation) enables remote procedure calls.
• Web services (SOAP and RESTful) allow cross-language communication.

Multithreaded

• Java supports multithreading to achieve multitasking.
• Multiple tasks can run simultaneously within the same program.
• Useful for games, servers, and shared-resource applications.

Open Source

• Java tools are free to use for compiling and running.
• Frameworks like Spring and Hibernate are open source and accelerate development.
• Popular IDEs include IntelliJ IDEA, Eclipse, and VS Code.

API-Based

• Java provides a rich standard library with pre-built classes and methods.
• Third-party APIs like Gson, iText, and payment gateways are also available.

Portable

• Java code is easy to carry from one platform to another because of WORA.

High Performance

• Bytecode is converted to native code by the JIT (Just-In-Time) compiler.
• The JIT compiler uses profiling to optimize hot code paths.

Object-Oriented

• Java supports OOP principles for code reuse and maintainability.
• Core OOP components:
  • Class
  • Object
  • Polymorphism
  • Inheritance
  • Interface and Abstraction
  • Encapsulation

Frequently Asked Questions

What is Java?

Java is a general-purpose, object-oriented, high-level programming language used to build desktop, web, mobile, and enterprise applications. It is designed around the WORA (Write Once, Run Anywhere) principle, which makes it platform-independent.

Who invented Java and when?

Java was created by James Gosling and his team at Sun Microsystems in 1991. It was originally called Oak. It was renamed Java in 1995 and is now owned by Oracle Corporation, which acquired Sun Microsystems in 2010.

What is the latest stable version of Java?

As of 2026, Java 25 LTS (released September 2025) is the latest Long-Term Support version and is the recommended choice for production applications. Java 26 is the latest non-LTS feature release. For most developers, Java 21 LTS or Java 25 LTS are the best choices.

Why is Java called platform-independent?

Java source code is compiled into bytecode, which runs on the Java Virtual Machine (JVM). Since the JVM is available for different operating systems, the same bytecode can run on any platform without recompilation — this is the WORA concept.

What are the main features of Java?

Java is simple, object-oriented, platform-independent, secure, robust, multithreaded, architecture-neutral, portable, and high-performance. It also supports distributed computing and automatic garbage collection.

Conclusion

Java remains one of the most important programming languages in 2026, thanks to its platform independence, strong ecosystem, and regular releases. Whether you are learning your first language or building enterprise systems, Java provides a stable, well-documented, and widely supported foundation.

For new projects, start with Java 25 LTS. If you need compatibility with older dependencies, Java 21 LTS or Java 17 LTS are safe choices. Avoid non-LTS releases like Java 26 for production unless you specifically need its features.

Related topics: Java Installation Guide, JDK vs JRE vs JVM, Java OOP Concepts, Java 8 Features, Java 21 Virtual Threads, Java 25 LTS Features