develop

Report.md

@@ -0,0 +1,65 @@
+# Assignment Report: Multithreading Basics
+### Course: Advanced Programming
+
+## Assignment: Eighth Assignment – Multithreading Basics
+
+Project: Simulated Download Manager
+
+1. Theoretical Questions
+   1.1 Difference Between start() and run()
+   In Java, the run() method contains the code that a thread should execute. However, calling run() directly does not create a new thread; it works like a normal method call in the current thread.
+
+When start() is called, the JVM creates a new thread, which then executes the run() method internally.
+
+1.2 Daemon Threads
+A daemon thread is a background thread. The JVM does not wait for daemon threads to finish. When all user threads finish, the JVM stops the program even if daemon threads are still running.
+
+If setDaemon(true) is removed, the thread becomes a normal user thread, and the JVM will wait for it to complete.
+
+1.3 Lambda Expressions for Threads
+A lambda expression is a concise way to implement a functional interface like Runnable. Since Runnable has only one method (run()), we can use:
+
+() -> { ... } instead of creating a whole new class.
+
+2. Practical Implementation
+   2.1 Project Overview
+   This project simulates a download manager where a file is divided into chunks, and each chunk is downloaded concurrently by separate worker threads.
+
+2.2 DownloadWorker
+The DownloadWorker class implements Runnable. It simulates the download of a single chunk by:
+
+Using random step sizes for download progress.
+Sleeping for random delays to simulate network latency.
+Updating its chunk status until the download is complete.
+2.3 ChunkStatus
+This class stores the state of each chunk, including its ID, size, and downloaded amount. Variables are marked as volatile to ensure visibility across different threads.
+
+2.4 ProgressMonitor
+The ProgressMonitor runs as a background thread to periodically check and print:
+
+Individual chunk progress.
+Total download percentage.
+A visual Progress Bar.
+Average download speed and ETA.
+2.5 Main Class
+The Main class coordinates the process:
+
+Reads configuration.
+Initializes chunks and worker threads.
+Starts the monitor and workers.
+Uses join() to wait for all threads to finish before printing the final report.
+3. Bonus Features
+   3.1 Progress Bar & ETA
+   A visual progress bar was added to the console output. The program also calculates the current speed in MB/s and estimates the remaining time (ETA) based on that speed.
+
+3.2 Sequential vs Multithreaded Comparison
+The program compares running the workers sequentially (using .run()) versus concurrently (using .start()). It calculates the Speedup to show how much faster multithreading is for this task.
+
+4. Execution Instructions
+   To compile and run the project, use the following commands:
+
+bash
+mvn compile
+mvn exec:java -Dexec.mainClass="Main"
+5. Conclusion
+   This project successfully demonstrates the power of multithreading in Java. By using separate threads for different chunks, the total download time is significantly reduced compared to a sequential approach.