What is meant by Thread?

In Java, a Thread is a lightweight subprocess—a unit of execution within a program that runs independently. Threads allow concurrent execution, meaning your program can perform multiple tasks at the same time, improving efficiency and responsiveness.

🧠 Why Use Threads?

Imagine you’re building a web application:

• One thread handles user input.
• Another fetches data from a database.
• A third updates the UI.

Without threads, these tasks would run one after the other, slowing everything down.

🧵 How to Create a Thread in Java

There are two main ways to create a thread:

1. By Extending the Thread Class

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(); // starts the thread
}

}

2. By Implementing the Runnable Interface

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

}

🔄 Thread Lifecycle

A thread goes through several states:

1. New – Created but not started.
2. Runnable – Ready to run.
3. Running – Currently executing.
4. Blocked/Waiting – Paused, waiting for resources.
5. Terminated – Finished execution.

🧪 Real-World Example

In a test automation project:

“I used threads to run multiple test cases in parallel. Each test case was executed in a separate thread, reducing total execution time and improving CI/CD pipeline efficiency.”