Added comments on multi-thread

src/main/java/multithread/MultiServer.java

@@ -5,16 +5,22 @@ import java.net.*;
 
 class MultiServer {
     public static void main(String argv[]) throws Exception {
+
+        /* Create a "listening socket" on the specified port */
         ServerSocket welcomeSocket = new ServerSocket(6789);
 
         while(true) {
+            /*
+             * Call to accept function (blocking call).
+             * When a new connection arrives a new "established socket" is created
+             */
             Socket connectionSocket = welcomeSocket.accept();
 
-            // thread creation passing the established socket as arg
+            /* Thread creation passing the established socket as argument */
             ServerThread theThread =
                     new ServerThread(connectionSocket);
 
-            // start of the thread
+            /* Start the thread*/
             theThread.start();
         }
     }

src/main/java/multithread/ServerThread.java

@@ -12,11 +12,16 @@ public class ServerThread extends Thread {
     public ServerThread(Socket s) {
         connectionSocket = s;
         try {
+
+            /* Initialize input stream from the socket */
             inFromClient =
                     new BufferedReader(
                             new InputStreamReader(connectionSocket.getInputStream()));
+
+            /* Initialize output stream towards the socket */
             outToClient =
                     new DataOutputStream(connectionSocket.getOutputStream());
+
         } catch (IOException e) {
             e.printStackTrace();
         }
@@ -26,9 +31,19 @@ public class ServerThread extends Thread {
         String clientSentence;
         String capitalizedSentence;
         try {
+            /* Read a line (ending with '\n') from the client */
             clientSentence = inFromClient.readLine();
+
+            /* simulate a processing time of 10 seconds*/
+            //Thread.sleep(10000);
+
+            /* Build the response */
             capitalizedSentence = clientSentence.toUpperCase() + '\n';
+
+            /* Send the response to the client */
             outToClient.writeBytes(capitalizedSentence);
+
+            /* Close the connection socket */
             connectionSocket.close();
         } catch (IOException e) {
             e.printStackTrace();