Creating Threads in Java

In Java, you can create threads using the Thread class or the Runnable interface. This tutorial explains both approaches with examples.

Step 1: Creating a Thread by Extending the Thread Class

To create a thread by extending the Thread class, you need to override its run() method. Below is an example:

    class MyThread extends Thread {
        @Override
        public void run() {
            for (int i = 0; i < 5; i++) {
                System.out.println("Thread running: " + i);
                try {
                    Thread.sleep(500); // Pause for 500 milliseconds
                } catch (InterruptedException e) {
                    System.out.println("Thread interrupted: " + e.getMessage());
                }
            }
        }
    }
    
    public class ThreadExample {
        public static void main(String[] args) {
            MyThread thread = new MyThread();
            thread.start(); // Start the thread
        }
    }

Step 2: Creating a Thread by Implementing the Runnable Interface

To create a thread by implementing the Runnable interface, you need to define the run() method and pass an instance of your class to a Thread object. Below is an example:

    class MyRunnable implements Runnable {
        @Override
        public void run() {
            for (int i = 0; i < 5; i++) {
                System.out.println("Runnable running: " + i);
                try {
                    Thread.sleep(500); // Pause for 500 milliseconds
                } catch (InterruptedException e) {
                    System.out.println("Thread interrupted: " + e.getMessage());
                }
            }
        }
    }
    
    public class RunnableExample {
        public static void main(String[] args) {
            MyRunnable myRunnable = new MyRunnable();
            Thread thread = new Thread(myRunnable);
            thread.start(); // Start the thread
        }
    }

Step 3: Using Anonymous Classes for Threads

For simpler use cases, you can create threads using anonymous classes. Below is an example:

    public class AnonymousThreadExample {
        public static void main(String[] args) {
            Thread thread = new Thread(new Runnable() {
                @Override
                public void run() {
                    for (int i = 0; i < 5; i++) {
                        System.out.println("Anonymous thread running: " + i);
                        try {
                            Thread.sleep(500); // Pause for 500 milliseconds
                        } catch (InterruptedException e) {
                            System.out.println("Thread interrupted: " + e.getMessage());
                        }
                    }
                }
            });
            thread.start(); // Start the thread
        }
    }

Step 4: Using Lambda Expressions for Threads (Java 8+)

If you are using Java 8 or later, you can use lambda expressions to simplify thread creation. Below is an example:

    public class LambdaThreadExample {
        public static void main(String[] args) {
            Thread thread = new Thread(() -> {
                for (int i = 0; i < 5; i++) {
                    System.out.println("Lambda thread running: " + i);
                    try {
                        Thread.sleep(500); // Pause for 500 milliseconds
                    } catch (InterruptedException e) {
                        System.out.println("Thread interrupted: " + e.getMessage());
                    }
                }
            });
            thread.start(); // Start the thread
        }
    }

Summary

In this tutorial, you learned:

  • How to create a thread by extending the Thread class
  • How to create a thread by implementing the Runnable interface
  • How to use anonymous classes and lambda expressions for thread creation

Threads are a fundamental part of concurrent programming in Java and can be created using multiple approaches to suit different use cases.




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