core1HelloWorld

1package pkg1core;2 3/*4 * core1HelloWorld.java5 * ----------------6 * The classic first program. Demonstrates the minimal structure of a Java app.7 *8 * EXPLANATION:9 *  - Every Java application starts in `public static void main(String[] args)`.10 *  - `public`  : the JVM must be able to call it from outside the class.11 *  - `static`  : no object needs to exist to call it.12 *  - `void`    : main returns nothing.13 *  - `String[] args` : command-line arguments.14 *15 * RUN:  java core1HelloWorld.java   (single-file launch)16 *   or: javac core1HelloWorld.java && java core1HelloWorld17 */18public class core1HelloWorld {19    public static void main(String[] args) {20        System.out.println("Hello, JavaMastery!");21 22        // Command-line args demo: try `java core1HelloWorld.java Alice`23        if (args.length > 0) {24            System.out.println("Hello, " + args[0] + "!");25        } else {26            System.out.println("(Tip: pass your name as an argument.)");27        }28    }29}