Difference Between Runnable and Thread in Java

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In Java, multithreading is one of the core features that allows programs to perform multiple tasks simultaneously. When learning how to create threads, you’ll encounter two commonly used approaches:

• Extending the Thread class
• Implementing the Runnable interface

Both are used to define and execute tasks in separate threads, but they are not the same and serve different design purposes.

In this article, we will explain the difference between Runnable and Thread in Java, their advantages and disadvantages, and when to use one over the other — with examples and a clear comparison table.

Introduction to Threading in Java

Multithreading in Java allows multiple parts of a program to execute concurrently, making applications more responsive and efficient — especially for tasks like I/O operations, file processing, or background services.

Java provides two main ways to create threads:

1. By extending the Thread class
2. By implementing the Runnable interface

Let’s look at both.

What is Thread in Java?