In Java, there are two primary ways to create a thread: by implementing the Runnable interface or by extending the Thread class. Let's compare these two approaches.
Implementing Runnable
Advantages:
- Better Design: Java supports single inheritance, so implementing
Runnable allows your class to extend another class if needed. - Promotes Code Reusability: Since you are not directly tied to the
Thread class, you can use the same Runnable implementation with different threading mechanisms (e.g., ExecutorService).
Example:
java
public class MyRunnable implements Runnable {
public void run() {
// Code to be executed in a separate thread
}
}
// Usage:
Thread myThread = new Thread(new MyRunnable());
myThread.start();
Extending Thread
Advantages:
- Simplicity: Extending the
Thread class can be simpler, as you don't need to create a separate object for the Runnable. - Direct Access to Thread Methods: Extending
Thread allows direct access to thread-related methods, but this can also be a disadvantage (see below).
Disadvantages:
- Limited Inheritance: Since Java supports single inheritance, extending
Thread limits the ability to extend other classes. - Less Flexible: Extending
Thread ties your code to a specific threading implementation, making it less flexible for future changes.
Example:
java
public class MyThread extends Thread {
public void run() {
// Code to be executed in a separate thread
}
}
// Usage:
MyThread myThread = new MyThread();
myThread.start();
General Recommendation
- Use
Runnable: It is generally recommended to implement Runnable over extending Thread for better design and flexibility. - When to Use: If you need to share the same
Runnable instance among multiple threads or want to utilize thread pooling. - Use
Thread: You can extend the Thread class when simplicity is crucial and you don't need the additional features provided by implementing Runnable.
In modern Java development, leveraging the Runnable interface and using executor services or other concurrency utilities is a more flexible and scalable approach.