Improved network stability and other related fixes:

* server: fixed that a critical errors ignored in user commands threads (now it will be added to the logs);
* network: fixed frozen user responses in some use cases;
* network: fixed accidental and incorrect user responses (only latest response will be used now);
* network: improved freeze logs, added problem method name and code's line number;
* cheats: removed outdated deck and card load logic (only init.txt commands supports now);
* cheats: fixed wrong priority after add card dialog (closes #11437);
* cheats: improved stability and random errors on cheat executes (related to #11437);
* docs: added details on network and thread logic, human feedback life cycle, etc (see HumanPlayer, ThreadExecutorImpl);

Mage/src/main/java/mage/cards/decks/DeckCardLists.java

@@ -1,18 +1,21 @@
-
 package mage.cards.decks;
 
+import mage.util.CardUtil;
+import mage.util.Copyable;
+
 import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  *
- * @author BetaSteward_at_googlemail.com
+ * @author BetaSteward_at_googlemail.com, JayDi85
  */
-public class DeckCardLists implements Serializable {
+public class DeckCardLists implements Serializable, Copyable<DeckCardLists> {
 
-    private String name;
-    private String author;
+    private String name = null;
+    private String author = null;
     private List<DeckCardInfo> cards = new ArrayList<>();
     private List<DeckCardInfo> sideboard = new ArrayList<>();
 
@@ -20,6 +23,23 @@ public class DeckCardLists implements Serializable {
     private DeckCardLayout cardLayout = null;
     private DeckCardLayout sideboardLayout = null;
 
+    public DeckCardLists() {
+    }
+
+    protected DeckCardLists(final DeckCardLists deck) {
+        this.name = deck.name;
+        this.author = deck.author;
+        this.cards = CardUtil.deepCopyObject(deck.cards);
+        this.sideboard = CardUtil.deepCopyObject(deck.sideboard);
+        this.cardLayout = CardUtil.deepCopyObject(deck.cardLayout);
+        this.sideboardLayout = CardUtil.deepCopyObject(deck.sideboardLayout);
+    }
+
+    @Override
+    public DeckCardLists copy() {
+        return new DeckCardLists(this);
+    }
+
     /**
      * @return The layout of the cards
      */

Mage/src/main/java/mage/game/Game.java

@@ -534,7 +534,6 @@ public interface Game extends MageItem, Serializable, Copyable<Game> {
 
     // game cheats (for tests only)
     void cheat(UUID ownerId, Map<Zone, String> commands);
-
     void cheat(UUID ownerId, List<Card> library, List<Card> hand, List<PermanentCard> battlefield, List<Card> graveyard, List<Card> command);
 
     // controlling the behaviour of replacement effects while permanents entering the battlefield

Mage/src/main/java/mage/game/GameImpl.java

@@ -794,7 +794,7 @@ public abstract class GameImpl implements Game {
                 if (!concedingPlayers.contains(playerId)) {
                     logger.debug("Game over for player Id: " + playerId + " gameId " + getId());
                     concedingPlayers.add(playerId);
-                    player.signalPlayerConcede();
+                    player.signalPlayerConcede(); // will be executed on next priority
                 }
             } else {
                 // no asynchronous action so check directly
@@ -3799,8 +3799,9 @@ public abstract class GameImpl implements Game {
                 for (Player playerObject : getPlayers().values()) {
                     if (playerObject.isHuman() && playerObject.canRespond()) {
                         playerObject.resetStoredBookmark(this);
-                        playerObject.abort();
                         playerObject.resetPlayerPassedActions();
+                        playerObject.abort();
+
                     }
                 }
                 fireUpdatePlayersEvent();

Mage/src/main/java/mage/game/GameState.java

@@ -77,7 +77,7 @@ public class GameState implements Serializable, Copyable<GameState> {
     private Turn turn;
     private TurnMods turnMods; // one time turn modifications (turn, phase or step)
     private UUID activePlayerId; // playerId which turn it is
-    private UUID priorityPlayerId; // player that has currently priority
+    private UUID priorityPlayerId; // player that has currently priority (setup before any choose)
     private UUID playerByOrderId; // player that has currently priority
     private UUID monarchId; // player that is the monarch
     private UUID initiativeId; // player that has the initiative

Mage/src/main/java/mage/players/Player.java

@@ -550,6 +550,8 @@ public interface Player extends MageItem, Copyable<Player> {
 
     void signalPlayerConcede();
 
+    void signalPlayerCheat();
+
     void skip();
 
     // priority, undo, ...

Mage/src/main/java/mage/players/PlayerImpl.java

@@ -5088,7 +5088,10 @@ public abstract class PlayerImpl implements Player, Serializable {
 
     @Override
     public void signalPlayerConcede() {
+    }
 
+    @Override
+    public void signalPlayerCheat() {
     }
 
     @Override

Mage/src/main/java/mage/util/DebugUtil.java

@@ -1,5 +1,7 @@
 package mage.util;
 
+import java.lang.reflect.Method;
+
 /**
  * Devs only: enable or disable debug features
  * <p>
@@ -28,4 +30,47 @@ public class DebugUtil {
     public static boolean GUI_GAME_DRAW_BATTLEFIELD_BORDER = false;
     public static boolean GUI_GAME_DRAW_HAND_AND_STACK_BORDER = false;
     public static boolean GUI_GAME_DIALOGS_DRAW_CARDS_AREA_BORDER = false;
+
+    public static String getMethodNameWithSource(final int depth) {
+        return TraceHelper.getMethodNameWithSource(depth);
+    }
+
 }
+
+/**
+ * Debug: allows to find a caller's method name
+ * <a href="https://stackoverflow.com/a/11726687/1276632">Original code</a>
+ */
+class TraceHelper {
+
+    private static Method m;
+
+    static {
+        try {
+            m = Throwable.class.getDeclaredMethod("getStackTraceElement", int.class);
+            m.setAccessible(true);
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+    public static String getMethodName(final int depth) {
+        try {
+            StackTraceElement element = (StackTraceElement) m.invoke(new Throwable(), depth + 1);
+            return element.getMethodName();
+        } catch (Exception e) {
+            e.printStackTrace();
+            return null;
+        }
+    }
+
+    public static String getMethodNameWithSource(final int depth) {
+        try {
+            StackTraceElement element = (StackTraceElement) m.invoke(new Throwable(), depth + 1);
+            return String.format("%s - %s:%d", element.getMethodName(), element.getFileName(), element.getLineNumber());
+        } catch (Exception e) {
+            e.printStackTrace();
+            return null;
+        }
+    }
+}