diff --git a/src/main/java/app/data/service/PlayerService.java b/src/main/java/app/data/service/PlayerService.java
index 153d649..3a5de23 100644
--- a/src/main/java/app/data/service/PlayerService.java
+++ b/src/main/java/app/data/service/PlayerService.java
@@ -44,9 +44,9 @@ public class PlayerService extends CrudService<Player, Integer> {
     }
 
     private class PlayerForTableProvider {
-        List<Matchday> matchdays = new ArrayList<>();
-        List<CalculatedMatch> calculatedMatches = new ArrayList<>();
-        List<Player> players = repository.findAll();
+        private final List<Matchday> matchdays = new ArrayList<>();
+        private final List<CalculatedMatch> calculatedMatches = new ArrayList<>();
+        private final List<Player> players = repository.findAll();
 
         public PlayerForTableProvider(Matchday matchday) {
             matchdays.addAll(matchdayService.getMatchdaysSorted(matchday.getSeason()).stream()
diff --git a/src/main/java/app/navigation/NavigationService.java b/src/main/java/app/navigation/NavigationService.java
index fee474f..4d270f9 100644
--- a/src/main/java/app/navigation/NavigationService.java
+++ b/src/main/java/app/navigation/NavigationService.java
@@ -2,5 +2,6 @@ package app.navigation;
 
 public interface NavigationService<T extends Navigation> {
     T getNewNavigation();
+
     AbstractNavigationHeader<T> getNewNavigationHeader(T navigation);
 }
diff --git a/src/main/java/app/navigation/NavigationUtils.java b/src/main/java/app/navigation/NavigationUtils.java
index 525ff5a..fdebc70 100644
--- a/src/main/java/app/navigation/NavigationUtils.java
+++ b/src/main/java/app/navigation/NavigationUtils.java
@@ -1,7 +1,6 @@
 package app.navigation;
 
 import app.utils.EntityStringUtils;
-import com.vaadin.flow.router.WildcardParameter;
 import org.springframework.lang.NonNull;
 
 import java.util.List;
diff --git a/src/main/java/app/navigation/match/MatchNavigation.java b/src/main/java/app/navigation/match/MatchNavigation.java
index 19056b4..69a484d 100644
--- a/src/main/java/app/navigation/match/MatchNavigation.java
+++ b/src/main/java/app/navigation/match/MatchNavigation.java
@@ -31,7 +31,7 @@ public class MatchNavigation extends Navigation {
     }
 
     @Override
-    @SuppressWarnings("unchecked")
+    @SuppressWarnings({"unchecked", "DuplicatedCode"}) // TODO: get rid of duplications
     protected <PARENT extends Navigable, CHILD extends Navigable> List<CHILD> getChildren(@Nullable PARENT parent, @NonNull Class<CHILD> childClass) {
         if (childClass.equals(Season.class)) {
             return (List<CHILD>) getSeasonService().getAllSeasonsSorted();
@@ -50,7 +50,7 @@ public class MatchNavigation extends Navigation {
     }
 
     @Override
-    @SuppressWarnings("unchecked")
+    @SuppressWarnings({"unchecked", "DuplicatedCode"}) // TODO: get rid of duplications
     protected <T extends Navigable> T getDefaultValue(Class<T> clazz) {
         if (clazz.equals(Season.class)) {
             assert !getSeasonList().isEmpty();
diff --git a/src/main/java/app/navigation/matchday/MatchdayNavigation.java b/src/main/java/app/navigation/matchday/MatchdayNavigation.java
index a52cbd4..2351456 100644
--- a/src/main/java/app/navigation/matchday/MatchdayNavigation.java
+++ b/src/main/java/app/navigation/matchday/MatchdayNavigation.java
@@ -1,9 +1,7 @@
 package app.navigation.matchday;
 
-import app.data.entity.Match;
 import app.data.entity.Matchday;
 import app.data.entity.Season;
-import app.data.service.MatchService;
 import app.data.service.MatchdayService;
 import app.data.service.SeasonService;
 import app.navigation.Navigable;
@@ -30,7 +28,7 @@ public class MatchdayNavigation extends Navigation {
     }
 
     @Override
-    @SuppressWarnings({"unchecked", "DuplicatedCode"})
+    @SuppressWarnings({"unchecked", "DuplicatedCode"}) // TODO: get rid of duplications
     protected <PARENT extends Navigable, CHILD extends Navigable> List<CHILD> getChildren(@Nullable PARENT parent, @NonNull Class<CHILD> childClass) {
         if (childClass.equals(Season.class)) {
             return (List<CHILD>) getSeasonService().getAllSeasonsSorted();
@@ -45,7 +43,7 @@ public class MatchdayNavigation extends Navigation {
     }
 
     @Override
-    @SuppressWarnings({"unchecked", "DuplicatedCode"})
+    @SuppressWarnings({"unchecked", "DuplicatedCode"}) // TODO: get rid of duplications
     protected <T extends Navigable> T getDefaultValue(Class<T> clazz) {
         if (clazz.equals(Season.class)) {
             assert !getSeasonList().isEmpty();
diff --git a/src/main/java/app/navigation/matchday/MatchdayNavigationService.java b/src/main/java/app/navigation/matchday/MatchdayNavigationService.java
index 4b11ed9..4d7085e 100644
--- a/src/main/java/app/navigation/matchday/MatchdayNavigationService.java
+++ b/src/main/java/app/navigation/matchday/MatchdayNavigationService.java
@@ -1,6 +1,5 @@
 package app.navigation.matchday;
 
-import app.data.service.MatchService;
 import app.data.service.MatchdayService;
 import app.data.service.SeasonService;
 import app.navigation.AbstractNavigationHeader;
diff --git a/src/main/java/app/navigation/matchday/components/button/NextMatchdayButton.java b/src/main/java/app/navigation/matchday/components/button/NextMatchdayButton.java
index 1ae222e..6d86783 100644
--- a/src/main/java/app/navigation/matchday/components/button/NextMatchdayButton.java
+++ b/src/main/java/app/navigation/matchday/components/button/NextMatchdayButton.java
@@ -1,7 +1,6 @@
 package app.navigation.matchday.components.button;
 
 import app.data.entity.Matchday;
-import app.navigation.match.MatchNavigation;
 import app.navigation.matchday.MatchdayNavigation;
 import com.vaadin.flow.component.button.Button;
 import com.vaadin.flow.component.icon.VaadinIcon;
diff --git a/src/main/java/app/navigation/matchday/components/button/PrevMatchdayButton.java b/src/main/java/app/navigation/matchday/components/button/PrevMatchdayButton.java
index 456d432..d1747c4 100644
--- a/src/main/java/app/navigation/matchday/components/button/PrevMatchdayButton.java
+++ b/src/main/java/app/navigation/matchday/components/button/PrevMatchdayButton.java
@@ -1,7 +1,6 @@
 package app.navigation.matchday.components.button;
 
 import app.data.entity.Matchday;
-import app.navigation.match.MatchNavigation;
 import app.navigation.matchday.MatchdayNavigation;
 import com.vaadin.flow.component.button.Button;
 import com.vaadin.flow.component.icon.VaadinIcon;
diff --git a/src/main/java/app/views/match/MatchView.java b/src/main/java/app/views/match/MatchView.java
index 3423451..5d71d83 100644
--- a/src/main/java/app/views/match/MatchView.java
+++ b/src/main/java/app/views/match/MatchView.java
@@ -1,8 +1,6 @@
 package app.views.match;
 
 import app.data.service.ChessComService;
-import app.data.service.GameInfoService;
-import app.data.service.GameService;
 import app.gameimage.GameImageService;
 import app.navigation.match.MatchNavigation;
 import app.navigation.match.MatchNavigationService;
diff --git a/src/main/java/app/views/matchday/MatchdayView.java b/src/main/java/app/views/matchday/MatchdayView.java
index 274eea4..e95dacf 100644
--- a/src/main/java/app/views/matchday/MatchdayView.java
+++ b/src/main/java/app/views/matchday/MatchdayView.java
@@ -1,6 +1,5 @@
 package app.views.matchday;
 
-import app.navigation.match.MatchNavigation;
 import app.navigation.matchday.MatchdayNavigation;
 import app.navigation.matchday.MatchdayNavigationService;
 import app.views.main.MainView;
diff --git a/src/main/java/app/views/matchday/components/MatchdayCard.java b/src/main/java/app/views/matchday/components/MatchdayCard.java
index 55cf202..623a105 100644
--- a/src/main/java/app/views/matchday/components/MatchdayCard.java
+++ b/src/main/java/app/views/matchday/components/MatchdayCard.java
@@ -2,7 +2,6 @@ package app.views.matchday.components;
 
 import app.data.bean.CalculatedMatch;
 import app.data.entity.Matchday;
-import app.navigation.match.MatchNavigation;
 import app.navigation.matchday.MatchdayNavigation;
 import app.navigation.matchday.components.button.NextMatchdayButton;
 import app.navigation.matchday.components.button.PrevMatchdayButton;
@@ -32,7 +31,7 @@ public class MatchdayCard extends Div implements ContentConfigurable {
     private final MatchdayNavigation matchdayNavigation;
 
     private final Calendar calendar = Calendar.getInstance();
-    SimpleDateFormat dateFormat = new SimpleDateFormat("dd.MM.");
+    private final SimpleDateFormat dateFormat = new SimpleDateFormat("dd.MM.");
 
     private final HorizontalLayout header = new HorizontalLayout();
     private final HorizontalLayout headerLabelLayout = new HorizontalLayout();
diff --git a/src/main/java/app/views/table/TableView.java b/src/main/java/app/views/table/TableView.java
index 954e990..0078e6d 100644
--- a/src/main/java/app/views/table/TableView.java
+++ b/src/main/java/app/views/table/TableView.java
@@ -1,7 +1,6 @@
 package app.views.table;
 
 import app.data.service.PlayerService;
-import app.navigation.match.MatchNavigationService;
 import app.navigation.matchday.MatchdayNavigation;
 import app.navigation.matchday.MatchdayNavigationService;
 import app.views.main.MainView;
diff --git a/src/main/java/app/views/table/components/TableCard.java b/src/main/java/app/views/table/components/TableCard.java
index 1d3e3dc..36816f9 100644
--- a/src/main/java/app/views/table/components/TableCard.java
+++ b/src/main/java/app/views/table/components/TableCard.java
@@ -3,7 +3,6 @@ package app.views.table.components;
 import app.data.bean.PlayerForTable;
 import app.data.entity.Matchday;
 import app.data.service.PlayerService;
-import app.navigation.match.MatchNavigation;
 import app.navigation.matchday.MatchdayNavigation;
 import app.navigation.matchday.components.button.NextMatchdayButton;
 import app.navigation.matchday.components.button.PrevMatchdayButton;