Write a Java program to demonstrate multithreading with Thread class and Runnable interface.

public class MyThread extends Thread {

    private String threadName;

    MyThread(String name) {
        this.threadName = name;
    }

    @Override
    public void run() {
        for (int i = 1; i <= 5; i++) {
            System.out.println(threadName + " → count: " + i);
            try {
                Thread.sleep(100);  // pause 100ms
            } catch (InterruptedException e) {
                System.out.println("Thread interrupted");
            }
        }
        System.out.println(threadName + " finished.");
    }

    public static void main(String[] args) {
        MyThread t1 = new MyThread("Thread-1");
        MyThread t2 = new MyThread("Thread-2");

        t1.start();  // starts new OS thread and calls run()
        t2.start();  // t1 and t2 run concurrently
    }
}

Thread-1 → count: 1
Thread-2 → count: 1
Thread-1 → count: 2
Thread-2 → count: 2
...

public class RunnableDemo implements Runnable {

    private String name;

    RunnableDemo(String name) { this.name = name; }

    @Override
    public void run() {
        for (int i = 1; i <= 3; i++) {
            System.out.println(name + ": step " + i +
                " [Thread: " + Thread.currentThread().getName() + "]");
        }
    }

    public static void main(String[] args) {
        Runnable task1 = new RunnableDemo("LoginTest");
        Runnable task2 = new RunnableDemo("CheckoutTest");

        Thread t1 = new Thread(task1, "Browser-1");
        Thread t2 = new Thread(task2, "Browser-2");

        t1.start();
        t2.start();

        // Wait for both threads to finish
        try {
            t1.join();
            t2.join();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        System.out.println("All tests completed");
    }
}

Thread t1 = new Thread(() -> {
    System.out.println("Running in: " + Thread.currentThread().getName());
}, "TestThread-1");

t1.start();

// Each thread gets its OWN driver — no sharing
public class DriverManager {
    private static final ThreadLocal<WebDriver> driver = new ThreadLocal<>();

    public static void setDriver(WebDriver d) { driver.set(d); }
    public static WebDriver getDriver()        { return driver.get(); }
    public static void quit()                  { driver.get().quit(); driver.remove(); }
}

// Thread 1 uses its own Chrome instance
// Thread 2 uses its own Firefox instance
// No interference between parallel tests