☕ Lesson 1: What is Java?
⏱️ Estimated time: 15 minutes | Difficulty: Beginner
Write Once, Run Anywhere
Java is a high-level, class-based, object-oriented programming language designed to have as few implementation dependencies as possible. It is famous for its "Write Once, Run Anywhere" (WORA) philosophy.
Java is Everywhere
Java is one of the most popular programming languages in the world. It runs on billions of devices — from Android phones to enterprise servers to IoT devices. Its motto: "Write Once, Run Anywhere!"
Why Learn Java?
- 🏢 Enterprise — Most large companies use Java backend systems
- 📱 Android — Primary language for Android app development
- 🔒 Type Safety — Catches errors before running
- 🌐 Cross-Platform — JVM runs on any operating system
- 💼 Jobs — One of the most in-demand programming skills
How Java Works
Java code is compiled to bytecode, which runs on the Java Virtual Machine (JVM). This is why Java works on any platform!
Your Code (.java) → Compile → Bytecode (.class) → JVM → Runs Anywhere!Java vs Other Languages
| Feature | Java | Python | C++ |
|---|---|---|---|
| Typing | Static | Dynamic | Static |
| Speed | Fast | Slower | Fastest |
| Memory | Managed (GC) | Managed | Manual |
| OOP | Required | Optional | Optional |