A Simple Java Thread Example Demonstrating Concurrent Execution

Question

Can someone provide a straightforward Java thread example that illustrates simultaneous execution of multiple threads?

public class ThreadExample {

    public static void main(String[] args) {
        // Create three threads
        Thread t1 = new Thread(new Task("Thread 1"));
        Thread t2 = new Thread(new Task("Thread 2"));
        Thread t3 = new Thread(new Task("Thread 3"));

        // Start the threads
        t1.start();
        t2.start();
        t3.start();
    }
}

class Task implements Runnable {
    private String threadName;

    Task(String name) {
        this.threadName = name;
    }

    @Override
    public void run() {
        for (int i = 1; i <= 5; i++) {
            System.out.println(threadName + " is running iteration " + i);
            try {
                Thread.sleep((int)(Math.random() * 1000)); // Sleep for a random time
            } catch (InterruptedException e) {
                System.out.println(threadName + " interrupted.");
            }
        }
    }
}

Answer

In Java, threading allows multiple threads of execution to run concurrently. This example illustrates the creation of three separate threads, providing a clear demonstration of their simultaneous operation.

public class ThreadExample {

    public static void main(String[] args) {
        // Create three threads
        Thread t1 = new Thread(new Task("Thread 1"));
        Thread t2 = new Thread(new Task("Thread 2"));
        Thread t3 = new Thread(new Task("Thread 3"));

        // Start the threads
        t1.start();
        t2.start();
        t3.start();
    }
}

class Task implements Runnable {
    private String threadName;

    Task(String name) {
        this.threadName = name;
    }

    @Override
    public void run() {
        for (int i = 1; i <= 5; i++) {
            System.out.println(threadName + " is running iteration " + i);
            try {
                Thread.sleep((int)(Math.random() * 1000)); // Sleep for a random time
            } catch (InterruptedException e) {
                System.out.println(threadName + " interrupted.");
            }
        }
    }
}

Causes

Threads are independent units of execution and can run concurrently.
Java's Thread class and Runnable interface facilitate concurrent execution.

Solutions

Define task logic in a runnable class.
Instantiate threads with the runnable implementation.
Use start() method to launch multiple threads.

Common Mistakes

Mistake: Forgetting to start a thread with start() method, using run() instead.

Solution: Always use start() to initiate thread execution.

Mistake: Incorrectly managing thread lifecycle, leading to deadlocks or resource issues.

Solution: Carefully design thread interactions and utilize concurrency controls where necessary.

Helpers

Java threads example
Java concurrent execution
multithreading in Java
Runnable interface Java
Java threading tutorial