How to Create Thread in Java

In this chapter of multithreading, we will learn How to create Thread in Java.

Multithreading is a concept of running more than one thread concurrently to perform any task. In Java, we can create threads using two ways:

1. Extending the Thread class
2. Implementing the Runnable Interface

1. How to Create Thread by extending the Thread class:

For creating a thread in Java extending the Thread class is a very common method and now we are going to design a class that extends java.lang.Thread class.

public class DemoClass extends Thread {
        //overriding the run() method from Thread Class
	public void run() {
		System.out.println("Thread is running");
	}

	public static void main(String[] args) {
		DemoClass object = new DemoClass();
                // starting thread
		object.start();
	}
}

Output:

Thread is running

2. How to Create Thread by implementing Runnable Interface:

For creating a thread in Java by implementing the Runnable Interface we need to override the run() method and now we are going to design a class that implements the Runnable Interface.

public class DemoClass implements Runnable{
	@Override
	public void run() {
		System.out.println("Thread is runnning");
	}

	public static void main(String[] args) {
		DemoClass obj = new DemoClass();
		Thread thread1 = new Thread(obj);
		thread1.start();
	}
}

Output:

Thread is running

3. Thread Class vs Runnable Interface

Here is an interesting question that what is the difference between creating a thread using Thread class and Runnable Interface?

Basically, there are two big reasons:

1. In Java, Multiple Inheritance is not supported i.e if you create a thread using Thread class, you can not extend any other class. Therefore, in that case, creating a thread using Runnable Interface is recommended.
2. But, while creating thread using Runnable Interface, you cannot achieve basic functionality like using methods that are available in Thread class like yield(), isAlive(), getState(), getId(), etc

I hope you understand how to Create Thread in Java. The creation of a thread through any of the method totally depends on your project requirement.

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