ThreadPrintingDemo.java

// 1. Creating a thread by EXTENDING the Thread class
class ThreadByExtension extends Thread {
    @Override
    public void run() {
        for (int i = 1; i <= 10; i++) {
            System.out.println("Extended Thread: " + i);
            
            // Brief pause to allow console output to mix, making concurrency visible
            try { Thread.sleep(50); } catch (InterruptedException e) {}
        }
    }
}

// 2. Creating a thread by IMPLEMENTING the Runnable interface
class ThreadByRunnable implements Runnable {
    @Override
    public void run() {
        for (int i = 1; i <= 10; i++) {
            System.out.println("Runnable Thread: " + i);
            
            try { Thread.sleep(50); } catch (InterruptedException e) {}
        }
    }
}

// 3. Main Driver Class (PascalCase)
public class ThreadPrintingDemo {
    public static void main(String[] args) {
        System.out.println("--- Starting Threads ---");

        // Instantiating the thread created via extension
        ThreadByExtension thread1 = new ThreadByExtension();

        // Instantiating the thread created via interface
        ThreadByRunnable runnableTask = new ThreadByRunnable();
        Thread thread2 = new Thread(runnableTask);

        // Starting both threads concurrently
        thread1.start();
        thread2.start();
    }
}