Fix and complete JavaDoc comments

src/main/java/it/polimi/ingsw/gc14/Model/Game.java

@@ -28,12 +28,20 @@ import it.polimi.ingsw.gc14.View.TUI.BorderStyle;
  */
 public class Game implements Serializable {
 
+    /**
+     * List of observers registered to receive updates when the game state changes.
+     *
+     * <p>The list is marked as {@code transient} because observers should not be
+     * serialized with the game model.
+     */
     private transient List<Observer> observers = new ArrayList<>(); // transient! non serializzare
 
+
     public void addObserver(Observer observer) {
         observers.add(observer);
     }
 
+
     private void notifyObservers() {
         for (Observer o : observers) {
             o.update(this);
@@ -42,7 +50,8 @@ public class Game implements Serializable {
 
     /**
      * Returns the list of players participating in the game.
-     * @return
+     *
+     * @return a copy of the list of players currently participating in the game.
      */
     public List<Player> getPlayers() {
         return playersList;
@@ -149,6 +158,7 @@ public class Game implements Serializable {
      *
      * @param Username the username of the player to search for.
      * @return the player with the specified username, or {@code null} if no such player exists.
+     * @throws IndexOutOfBoundsException if an index access error occurs.
      */
     public Player getPlayerByUsername(String Username) throws IndexOutOfBoundsException {
         return playersList.stream().filter(x->x.getUserName().equals(Username)).findFirst().orElse(null);