Two threads executed but expected one

[Martin Johansson]

I'm quite new to threads and just wonder why this example executes 2 threads when I expect 1 thread to be executed

// HttpServer class
public class HttpServer {

	public static void main(String[] args) throws IOException {

		/**
		 * Port number.
		 *
		 * @var int
		 */
		final int PORT = 9898;

		try {

			/**
			 * Create a server socket and bind it to a specific port
			 *
			 * @param PORT
			 */
			ServerSocket listener = new ServerSocket(PORT);
			System.out.println("Listens to port " + PORT + "...");

			while(true) {

				Socket socket = listener.accept();

				try {

					/**
					* Listen for the specified port and accepts it.
					* It also instansiate an HttpRequest object and pass the
					* Socket as an argument.
					*
					* @param Socket
					*/
					HttpRequest request = new HttpRequest(socket);

					/**
					* Allocates a new Thread object
					*
					* @param HttpRequest
					*/
					Thread thread = new Thread(request);

					/**
					* Start thread, begin execution.
					*/
					System.out.println(thread.getName()); // For testing
					thread.start();

				} catch(IOException e) {

					e.printStackTrace();

				}

			}

		} catch (IOException e) {

			e.printStackTrace();

		}

	}

}

// HttpRequest class
public class HttpRequest implements Runnable {

	/**
	 * Local variables
	 *
	 * @var Socket
	 * @var ProcessData
	 */
	private Socket socket;
	private ProcessData data;


	/**
	 * Constructor.
	 *
	 * @param Socket
	 */
	public HttpRequest(Socket socket) throws SocketException {

		this.socket = socket;
		data = new ProcessData();

	}

	/**
	 * Run method. 
	 * When thread is started the run method is executed.
	 */
	@Override
	public void run() {

		try {

			data.processRequest(socket);

		} catch (IOException e) {

			e.printStackTrace();

		}
	}

}

Output from from HttpServer class:
Thread-1
Thread-2

Expected output:
Thread-1

What am I doing wrong?

[Paul Clapham]

Hi Martin, welcome to the Ranch!

So, what are you doing wrong? You're expecting the wrong output. Your server code is telling you that two connections have been made to your server. For some reason you're under the impression that only one connection was made, but you haven't posted any code which shows how the connections are being made, so it's impossible to tell why you might incorrectly think that.

[Martin Johansson]

Paul Clapham wrote:Hi Martin, welcome to the Ranch!

So, what are you doing wrong? You're expecting the wrong output. Your server code is telling you that two connections have been made to your server. For some reason you're under the impression that only one connection was made, but you haven't posted any code which shows how the connections are being made, so it's impossible to tell why you might incorrectly think that.

Thank you.

When the code above is executed and I type http://localhost:9898 in the browser, a connection is established but I thought just one thread would execute, not two. Maybe I write the code in the wrong way?

[Paul Clapham]

You're assuming that your browser only sends one request to the URL. Confirm that assumption.

[Martin Johansson]

Paul Clapham wrote:You're assuming that your browser only sends one request to the URL. Confirm that assumption.

When I "inspect element" and check the "network tab" in chrome it says that 1 request is done, but still 2 threads are created to handle the request in my code.

[Jeff Verdegan]

Rather than guessing or relying on what Chrome tells you, get the answer straight from the source. Print out the details of each request that you process--which IP and port it came from, whether it's a GET, POST, etc., any parameters, and so on.