🟢 Foundation · Lesson 01
Introduction to Java
Introduction to Java
What is Java?
Java is a high-level, object-oriented, platform-independent programming language created by James Gosling at Sun Microsystems in 1995 (now owned by Oracle). Its famous principle is WORA — Write Once, Run Anywhere: compiled Java runs on any device that has a JVM.
Java powers Android apps, enterprise web systems, banking software and huge backend platforms. It is one of the most in-demand languages for jobs in India and worldwide.
Key Features of Java
| Feature | Meaning |
|---|---|
| Platform Independent | Bytecode runs on any OS via the JVM |
| Object-Oriented | Everything is built around classes and objects |
| Simple & Secure | No pointers; runs in a safe JVM sandbox |
| Robust | Strong type checking and automatic garbage collection |
| Multithreaded | Can run many tasks at once |
Where Java is Used
Android Apps
Most Android apps are built with Java/Kotlin
Most Android apps are built with Java/Kotlin
Web Backends
Spring, Jakarta EE enterprise systems
Spring, Jakarta EE enterprise systems
Banking & Finance
Secure, reliable transaction systems
Secure, reliable transaction systems
Big Data
Hadoop and large-scale tools
Hadoop and large-scale tools
Summary
- Java is object-oriented and platform-independent (WORA).
- Created in 1995; now owned by Oracle.
- Used in Android, web backends, banking and big data.
Java क्या है?
Java एक high-level, object-oriented, platform-independent programming language है जिसे James Gosling ने 1995 में Sun Microsystems में बनाया (अब Oracle के पास)। इसका मशहूर सिद्धांत है WORA — Write Once, Run Anywhere: compiled Java किसी भी device पर चलता है जिसमें JVM हो।
Java Android apps, enterprise web systems, banking software और बड़े backend platforms चलाता है। यह India और दुनिया भर में jobs के लिए सबसे ज़्यादा माँग वाली languages में से एक है।
Java की मुख्य Features
| Feature | मतलब |
|---|---|
| Platform Independent | Bytecode JVM से किसी भी OS पर चलता है |
| Object-Oriented | सब कुछ classes और objects पर आधारित |
| Simple & Secure | कोई pointers नहीं; safe JVM sandbox में चलता है |
| Robust | मज़बूत type checking और automatic garbage collection |
| Multithreaded | कई tasks एक साथ चला सकता है |
Java कहाँ Use होती है
Android Apps
ज़्यादातर Android apps Java/Kotlin में
ज़्यादातर Android apps Java/Kotlin में
Web Backends
Spring, Jakarta EE enterprise systems
Spring, Jakarta EE enterprise systems
Banking & Finance
Secure, reliable transaction systems
Secure, reliable transaction systems
Big Data
Hadoop और large-scale tools
Hadoop और large-scale tools
सारांश
- Java object-oriented और platform-independent है (WORA)।
- 1995 में बनी; अब Oracle के पास।
- Android, web backends, banking और big data में use होती है।