Multithreading in Java

// Way 1: Extend the Thread class
class MyThread extends Thread {
    public void run() {
        System.out.println("Running in: " + Thread.currentThread().getName());
    }
}
MyThread t1 = new MyThread();
t1.start();

// Way 2: Implement the Runnable interface
class MyTask implements Runnable {
    public void run() {
        System.out.println("Running in: " + Thread.currentThread().getName());
    }
}
Thread t2 = new Thread(new MyTask());
t2.start();

// Way 2b: Runnable with a lambda expression
Thread t3 = new Thread(() -> System.out.println("Lambda thread running"));
t3.start();

public class MultithreadingDemo {

    static class Worker implements Runnable {
        private final String label;
        Worker(String label) { this.label = label; }
        public void run() {
            System.out.println(label + " running on " + Thread.currentThread().getName());
        }
    }

    public static void main(String[] args) throws InterruptedException {
        Thread t1 = new Thread(new Worker("Task-A"), "Worker-1");
        Thread t2 = new Thread(new Worker("Task-B"), "Worker-2");

        // Using start() creates real new threads
        t1.start();
        t2.start();

        // Wait for both threads to finish before continuing
        t1.join();
        t2.join();

        // Contrast: calling run() directly does NOT create a new thread
        Worker directCall = new Worker("Task-C (direct run())");
        directCall.run();

        System.out.println("Main thread (" + Thread.currentThread().getName() + ") finished.");
    }
}

Task-A running on Worker-1
Task-B running on Worker-2
Task-C (direct run()) running on main
Main thread (main) finished.

(Note: The order of "Task-A" and "Task-B" lines can vary between runs
because the two threads are scheduled independently by the JVM/OS.)