Extends Thread Vs Implements Runnable | Java

When considering the choice between extending the Thread class and implementing the Runnable interface in Java, it's important to understand their implications and benefits.

Extends Thread

Extending the Thread class means creating a new class that directly inherits from the Thread class. This approach allows you to override and customize various methods provided by the Thread class. However, it also means that all methods and fields of the Thread class are inherited by your class, which may not be necessary and can introduce additional overhead. In many cases, this inheritance is not required, leading to inefficient use of system resources.

Implements Runnable

Implementing the Runnable interface involves creating a separate class that implements the Runnable interface and provides its own implementation for the run() method. This approach promotes better code organization and separation of concerns. By implementing the Runnable interface, your class becomes a "task" that can be executed by a thread. This allows for a more flexible and scalable design, as the same Runnable instance can be used to create multiple threads, if needed.

Implementing the Runnable interface offers advantages such as improved code reusability and maintainability. It enables decoupling of the task logic from the threading mechanism, making the code more modular and easier to test. Additionally, it facilitates better utilization of system resources by separating the task execution from the thread management.


Implementing the Runnable interface is often considered a better practice in Java, as it promotes cleaner code structure, improved flexibility, and reduced overhead compared to extending the Thread class.