Building a Simple Multithreaded Application

Welcome back to our journey into Java concurrency! So far, you've learned about creating threads, managing their lifecycle, and synchronizing shared data. Today, we will apply these concepts by building a simple multithreaded application. This project will give you practical experience with real-world concurrency in Java and demonstrate how to use synchronization effectively for safe data sharing.

In this project, you will:

• Implement a class that simulates a file download operation.
• Create and manage multiple threads to perform concurrent downloads.
• Use thread synchronization to manage output and prevent message overlap.
• Set thread priorities and observe their impact on thread scheduling.

By the end of this project, you'll have the skills to build a basic multithreaded application and understand key concurrency concepts in a practical setting.

You will create a Downloader class that simulates file downloads. The class will implement the Runnable interface, allowing it to be run by multiple threads. A Main class will manage these threads and coordinate their completion.

First, we'll create a Downloader class to simulate the downloading process. This class will implement the Runnable interface to be run within threads. We will split its implementation for clarity.

import java.util.Random;

public class Downloader implements Runnable {
    private final String fileName;
    private final Random rnd;

    public Downloader(String fileName) {
        this.fileName = fileName;
        this.rnd = new Random();
    }
}

In this snippet, we declare the class fields: fileName, which holds the name of the file to be downloaded, and rnd, a Random object used to simulate variable download times. The constructor initializes these fields, setting up the Downloader instance with the specified file name.