If you’re diving into Java programming, one of the most empowering features to understand is multithreading. It allows you to run multiple tasks concurrently, making your application more efficient and responsive. In this post, we’ll walk you through how to create threads in Java, using both the Thread class and the Runnable interface.

Why Multithreading Matters in Java

Multithreading helps your program perform multiple operations simultaneously. Think of downloading files, processing data, and updating the UI all at once. Without multithreading, these tasks would run one after the other, slowing everything down.

Java makes multithreading easy thanks to built-in support via the Thread class and the Runnable interface.

Method 1: Using the Thread Class

This is the most direct way to create a thread in Java.

Step-by-step:

1. Extend the Thread class.
2. Override the run() method.
3. Create an object of your class.
4. Call the start() method.

class MyThread extends Thread {
    public void run() {
        System.out.println("Thread is running...");
    }

    public static void main(String[] args) {
        MyThread t1 = new MyThread();
        t1.start();
    }
}

What Happens Here?

• run() defines the code that runs in the new thread.
• start() creates a new thread and invokes run().
• If you call run() directly, it runs in the main thread, not a new one.

This method is simple but has a limitation: your class can’t extend any other class since Java doesn’t support multiple inheritance.

Method 2: Implementing the Runnable Interface

A more flexible way to create threads in Java is by implementing the Runnable interface.

Step-by-step:

1. Implement Runnable.
2. Override the run() method.
3. Pass the object to a Thread constructor.
4. Start the thread.

class MyRunnable implements Runnable {
    public void run() {
        System.out.println("Runnable thread is running...");
    }

    public static void main(String[] args) {
        MyRunnable myRunnable = new MyRunnable();
        Thread t1 = new Thread(myRunnable);
        t1.start();
    }
}

Why Use Runnable?

• It allows your class to extend another class while still supporting threads.
• It separates the task (logic in run()) from the thread execution (managed by Thread).

Thread Class vs Runnable Interface: Quick Comparison

Pro Tip: Use Anonymous Classes or Lambdas (Java 8+)

If you’re working with short-lived tasks, you don’t need to write a separate class.

Anonymous Runnable:

Thread t = new Thread(new Runnable() {
    public void run() {
        System.out.println("Anonymous thread running");
    }
});
t.start();

Lambda Runnable (Java 8+):

Thread t = new Thread(() -> {
    System.out.println("Lambda thread running");
});
t.start();

Best Practices for Creating Threads in Java

• Avoid calling run() directly. Use start() to ensure a new thread is created.
• Use Runnable when possible. It offers better design flexibility.
• Name your threads. This makes debugging easier: Thread t = new Thread(runnable, "WorkerThread");
• Use thread pools for many threads. For heavy-duty multithreading, look into ExecutorService.

Want more details? Check out the full guide: [Main Article URL]

Conclusion

Learning how to create threads in Java isn’t just about writing concurrent code. It’s about writing efficient, clean, and scalable applications.

Start with Thread if you’re just experimenting. Move to Runnable for better design. Embrace lambdas and anonymous classes for quick jobs.

Multithreading is a key skill in Java. Master it, and you unlock a whole new level of performance for your applications.

FAQ: How to Create Threads in Java

Q: Can I start a thread without creating a class?
A: Yes, use anonymous classes or lambdas.

Q: What happens if I call run() instead of start()?
A: The code runs in the main thread, not in a new thread.

Q: Is Runnable better than Thread?
A: Usually yes. It gives more design flexibility and aligns with best practices.