Java ka Introduction

Java ek compiled, statically typed, garbage-collected language hai jo directly machine code mein compile nahi hoti — yeh bytecode mein compile hoti hai, jo Java Virtual Machine (JVM) par chalta hai. Yahi Java ke signature promise ka source hai, 'write once, run anywhere': wahi compiled bytecode kisi bhi platform par bina modify kiye chalta hai jahan JVM installed ho.

C++ ke ulat, jo aapko raw pointers aur manual memory management deta hai, Java mein koi pointers nahi hain jinhe aap directly manipulate kar sako aur koi manual delete nahi hai — garbage collector memory ko automatically reclaim kar leta hai jab koi bhi object ko reference nahi karta. Yeh tradeoff Java ko samajhne ke liye central hai: yeh C++ ke low-level control ka kuch hissa memory safety aur simplicity ke liye trade karta hai.

Ek jaldi sa preview

Yeh raha ek real Java program, jo is page ke apne compiler par actually run hua hai — koi mockup nahi:

public class Main {
    public static void main(String[] args) {
        String message = "Hello from Java!";
        System.out.println(message);
    }
}

Hello from Java!

Bas itna hi — ek String variable, jo System.out.println se print kiya gaya. Agla lesson aapka pehla poora program run karta hai aur exactly samjhaata hai ki kya ho raha hai.