"implements Runnable" vs "extends Thread" in Java

🔍 Understanding the Difference: "implements Runnable" vs "extends Thread" in Java 🔍

Are you confused about the difference between using "implements Runnable" and "extends Thread" in Java when creating threads? 🧐 Don't worry, you're not alone! This blog post will break down these two approaches, address common issues, provide easy solutions, and help you choose the right one for your needs. Let's dive in! 🚀

What's the Deal with "implements Runnable" and "extends Thread"?

With implements Runnable:

public class MyRunnable implements Runnable {
    public void run() {
         // Code
    }
}

// Started with a "new Thread(new MyRunnable()).start()" call

Or, with extends Thread:

public class MyThread extends Thread {
    public MyThread() {
        super("MyThread");
    }
    public void run() {
        // Code
    }
}

// Started with a "new MyThread().start()" call

At first glance, the code structure may seem similar, but there's a significant difference between the two approaches.

The Difference Explained:

🔹 Responsibility: When you implement the Runnable interface, your class is separate from the Thread class. It gives you the freedom to inherit from another class if needed. On the other hand, when you extend the Thread class, your class becomes the actual thread, and you can't inherit from any other class.

🔹 Code Reusability: Implementing Runnable allows you to separate the thread's functionality from the thread itself. You can reuse the same Runnable class with different threads, improving code maintainability and promoting cleaner design. Extending Thread, however, creates a tight coupling between the functionality and the thread, limiting code reuse.

🔹 Interface vs. Inheritance: Java supports multiple interfaces, but it doesn't support multiple inheritance. By implementing Runnable, you can still implement other interfaces in your class, ensuring your code can benefit from different functionality. If you extend Thread, you lose the ability to inherit from any other class.

🔹 Thread Pooling: When using implements Runnable, you can submit instances of Runnable to thread pools for better thread management. With extends Thread, you can't submit threads to thread pools directly.

Handling Common Issues:

Issue 1: What if I need to pass values to my thread?

You can pass values by creating a constructor in the class that implements Runnable and setting instance variables before starting the thread. This way, the thread can access the desired values during its execution.

Issue 2: How can I handle exceptions in my thread code?

Exception handling is similar for both approaches. You can enclose your thread code inside a try-catch block or throw any exceptions from the run() method's signature. Remember to handle or propagate the exceptions appropriately.

Choosing the Right Approach:

💡 If you need better code organization, flexibility to inherit from other classes, implement multiple interfaces, or utilize thread pooling, then implements Runnable is the way to go.

💡 On the other hand, if you have a simple standalone thread and don't require any additional flexibility, extends Thread can be a convenient option.

Conclusion:

Now you know the difference between using implements Runnable and extends Thread in Java. 😎 You've learned about their pros and cons, as well as how to handle common issues that may arise.

So, what approach will you use in your code? Let us know in the comments below! 👇 And if you found this blog post helpful, be sure to share it with your fellow Java developers. Let's spread the knowledge! 🌟