diff --git a/Mage.Client/src/main/java/mage/client/dialog/TableWaitingDialog.java b/Mage.Client/src/main/java/mage/client/dialog/TableWaitingDialog.java
index 0a7989ba0f2..3759569a6d3 100644
--- a/Mage.Client/src/main/java/mage/client/dialog/TableWaitingDialog.java
+++ b/Mage.Client/src/main/java/mage/client/dialog/TableWaitingDialog.java
@@ -299,7 +299,7 @@ public class TableWaitingDialog extends MageDialog {
 }
 
 class TableWaitModel extends AbstractTableModel {
-    private String[] columnNames = new String[]{"Seat Num", "Player Name", "Player Type"};
+    private final String[] columnNames = new String[]{"Seat Num", "Player Name", "Player Type"};
     private SeatView[] seats = new SeatView[0];
 
     public void loadData(TableView table) {
@@ -362,10 +362,10 @@ class TableWaitModel extends AbstractTableModel {
 
 class UpdateSeatsTask extends SwingWorker<Void, TableView> {
 
-    private Session session;
-    private UUID roomId;
-    private UUID tableId;
-    private TableWaitingDialog dialog;
+    private final Session session;
+    private final UUID roomId;
+    private final UUID tableId;
+    private final TableWaitingDialog dialog;
     private int count = 0;
 
     private static final Logger logger = Logger.getLogger(TableWaitingDialog.class);
diff --git a/Mage.Server/src/main/java/mage/server/ChatManager.java b/Mage.Server/src/main/java/mage/server/ChatManager.java
index c3707941a79..2c3cb7c3c3a 100644
--- a/Mage.Server/src/main/java/mage/server/ChatManager.java
+++ b/Mage.Server/src/main/java/mage/server/ChatManager.java
@@ -69,7 +69,9 @@ public class ChatManager {
     }
 
     public void destroyChatSession(UUID chatId) {
-        chatSessions.remove(chatId);
+        if (chatId != null) {
+            chatSessions.remove(chatId);
+        }
     }
 
     public void broadcast(UUID chatId, String userName, String message, MessageColor color) {
diff --git a/Mage.Server/src/main/java/mage/server/TableManager.java b/Mage.Server/src/main/java/mage/server/TableManager.java
index 0a0c3ad755c..0f8e8c8256b 100644
--- a/Mage.Server/src/main/java/mage/server/TableManager.java
+++ b/Mage.Server/src/main/java/mage/server/TableManager.java
@@ -204,7 +204,8 @@ public class TableManager {
 
     public boolean removeTable(UUID userId, UUID tableId) {
         if (isTableOwner(tableId, userId) || UserManager.getInstance().isAdmin(userId)) {
-            leaveTable(userId, tableId);
+            leaveTable(userId, tableId);            
+            ChatManager.getInstance().destroyChatSession(controllers.get(tableId).getChatId());  
             removeTable(tableId);
             return true;
         }
@@ -246,6 +247,8 @@ public class TableManager {
     public void startMatch(UUID userId, UUID roomId, UUID tableId) {
         if (controllers.containsKey(tableId)) {
             controllers.get(tableId).startMatch(userId);
+            // chat of start dialog can be killed
+            ChatManager.getInstance().destroyChatSession(controllers.get(tableId).getChatId());            
         }
     }
 
@@ -264,6 +267,7 @@ public class TableManager {
     public void startTournament(UUID userId, UUID roomId, UUID tableId) {
         if (controllers.containsKey(tableId)) {
             controllers.get(tableId).startTournament(userId);
+            ChatManager.getInstance().destroyChatSession(controllers.get(tableId).getChatId());     
         }
     }
 
@@ -334,9 +338,10 @@ public class TableManager {
     public void removeTable(UUID tableId) {
         if (tables.containsKey(tableId)) {
             Table table = tables.get(tableId);
+            ChatManager.getInstance().destroyChatSession(controllers.get(tableId).getChatId());  
             controllers.remove(tableId);
             tables.remove(tableId);
-            // If table is not finished, the table has to removed completly (if finished it will be removed in GamesRoomImpl.Update())
+                // If table is not finished, the table has to be removed completly (if finished it will be removed in GamesRoomImpl.Update())
             if (!table.getState().equals(TableState.FINISHED)) {
                 GamesRoomManager.getInstance().removeTable(tableId);
             }
diff --git a/Mage.Server/src/main/java/mage/server/game/GamesRoomManager.java b/Mage.Server/src/main/java/mage/server/game/GamesRoomManager.java
index 6ca6fc5b345..a771eed2cff 100644
--- a/Mage.Server/src/main/java/mage/server/game/GamesRoomManager.java
+++ b/Mage.Server/src/main/java/mage/server/game/GamesRoomManager.java
@@ -40,8 +40,8 @@ public class GamesRoomManager {
     private static final GamesRoomManager INSTANCE = new GamesRoomManager();
 //    private static final Logger logger = Logger.getLogger(GamesRoomManager.class);
 
-    private ConcurrentHashMap<UUID, GamesRoom> rooms = new ConcurrentHashMap<UUID, GamesRoom>();
-    private UUID mainRoomId;
+    private final ConcurrentHashMap<UUID, GamesRoom> rooms = new ConcurrentHashMap<>();
+    private final UUID mainRoomId;
 
     public static GamesRoomManager getInstance() {
         return INSTANCE;
diff --git a/Mage/src/mage/abilities/effects/ContinuousRuleModifiyingEffectImpl.java b/Mage/src/mage/abilities/effects/ContinuousRuleModifiyingEffectImpl.java
index c0f5477b569..8606e2bcd10 100644
--- a/Mage/src/mage/abilities/effects/ContinuousRuleModifiyingEffectImpl.java
+++ b/Mage/src/mage/abilities/effects/ContinuousRuleModifiyingEffectImpl.java
@@ -70,7 +70,7 @@ public abstract class ContinuousRuleModifiyingEffectImpl extends ContinuousEffec
     @Override
     public String getInfoMessage(Ability source, Game game) {
         if (infoMessage == null) {
-            String message = null;
+            String message;
             MageObject object = game.getObject(source.getSourceId());
             if (object != null) {
                 message = source.getRule(object.getLogName());