Introduction to Java – The Language That Powers the World

What is Java?

Java is a high-level, object-oriented, platform-independent programming language created by Sun Microsystems in 1995 (now owned by Oracle). It’s known for its slogan:

“Write Once, Run Anywhere.”

This means the same Java code can run on any device that has the Java Virtual Machine (JVM).

🛠️ Why Learn Java?

• 🔒 Widely used in enterprise software, Android apps, web apps, and IoT
• 🌐 Cross-platform capability (Windows, Mac, Linux)
• 💼 High demand in the job market
• ⚙️ Strong ecosystem (Spring, Hibernate, Maven, etc.)
• 💻 Excellent for learning object-oriented programming

📥 Step-by-Step: Setting Up Java on Your Machine

1. Download and Install JDK

• Go to: https://www.oracle.com/java/technologies/javase-downloads.html
• Download the latest JDK (Java Development Kit) for your OS
• Install it and note down the installation path

2. Set Environment Variables (Windows)

• Open System Properties > Environment Variables
• Add:
  • JAVA_HOME → your JDK path
  • Add %JAVA_HOME%\bin to the Path variable

java -version
javac -version

You should see the installed Java version printed.

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4. Choose Your IDE

• IntelliJ IDEA (recommended): fast, modern, and powerful
• Eclipse: classic and widely used
• VS Code: lightweight, with Java plugins

💡 First Java Program: Hello World

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, world!");
    }
}

Compile

javac HelloWorld.java

Run

java HelloWorld

✅ What You Learned

• What Java is and why it’s powerful
• How to install JDK
• How to run your first Java program