Made all implemented classes final.

src/main/java/connect/src/TCPClient.java

@@ -10,7 +10,7 @@ import java.net.*;
 
 import org.json.JSONObject;
 
-public class TCPClient {
+public final class TCPClient {
 
     private final int MIN_PORT = 1;
     private final int MAX_PORT = 65535;

src/main/java/gui/src/constants/GUIConstants.java

@@ -5,7 +5,7 @@
 
 package gui.src.constants;
 
-public class GUIConstants {
+public final class GUIConstants {
     /**
      * Represents kinds of frames.
      */

src/main/java/gui/src/frames/MainFrame.java

@@ -18,7 +18,7 @@ import gui.src.panels.MonitoringPanel;
 import java.awt.GridBagLayout;
 import java.awt.GridBagConstraints;
 
-public class MainFrame extends JFrame implements Themeable {
+public final class MainFrame extends JFrame implements Themeable {
 
     private static MainFrame instance;
 

src/main/java/gui/src/menubar/Menu.java

@@ -15,7 +15,7 @@ import gui.src.interfaces.Translateable;
 /**
  * Menu at menu bar.
  */
-public class Menu extends JMenu implements Translateable {
+public final class Menu extends JMenu implements Translateable {
     private String[] translations = null;
 
     /**

src/main/java/gui/src/menubar/MenuBar.java

@@ -14,7 +14,7 @@ import gui.src.interfaces.Translateable;
 import gui.src.menubar.menus.HelpMenuFactory;
 import gui.src.menubar.menus.LanguageMenuFactory;
 
-public class MenuBar extends JMenuBar implements Translateable {
+public final class MenuBar extends JMenuBar implements Translateable {
 
     private MenuBarLanguageController languageController = null;
 

src/main/java/gui/src/menubar/MenuBarLanguageController.java

@@ -5,7 +5,7 @@
 
 package gui.src.menubar;
 
-public class MenuBarLanguageController {
+public final class MenuBarLanguageController {
     private MenuBar menuBar = null;
 
     public MenuBarLanguageController(MenuBar menuBar) {

src/main/java/gui/src/menubar/MenuBarSeparator.java

@@ -14,7 +14,7 @@ import javax.swing.JMenuItem;
 /**
  * Horizontal line separator for menu bar.
  */
-public class MenuBarSeparator extends JMenuItem {
+public final class MenuBarSeparator extends JMenuItem {
 
     static final Color color = new Color(47, 47, 47);
 

src/main/java/gui/src/menubar/MenuItem.java

@@ -15,7 +15,7 @@ import gui.src.interfaces.Translateable;
 /**
  * Menu item at menu at menu bar.
  */
-public class MenuItem extends JMenuItem implements Translateable {
+public final class MenuItem extends JMenuItem implements Translateable {
     private String[] translations = null;
 
     /**

src/main/java/gui/src/menubar/menuItems/HelpMenuItemFactory.java

@@ -10,7 +10,7 @@ import java.awt.event.ActionListener;
 
 import gui.src.menubar.MenuItem;
 
-public class HelpMenuItemFactory {
+public final class HelpMenuItemFactory {
 
     public static MenuItem createManualMenuItem() {
         final String[] translations = {"Anleitung", "Manual"};

src/main/java/gui/src/menubar/menuItems/LanguageMenuItemFactory.java

@@ -12,7 +12,7 @@ import gui.src.constants.GUIConstants.Languages;
 import gui.src.menubar.MenuBarLanguageController;
 import gui.src.menubar.MenuItem;
 
-public class LanguageMenuItemFactory {
+public final class LanguageMenuItemFactory {
 
     public static MenuItem createGermanMenuItem(final MenuBarLanguageController languageController) {
         final String[] translations = {"Deutsch", "German"};

src/main/java/gui/src/menubar/menus/HelpMenuFactory.java

@@ -11,7 +11,7 @@ import java.awt.event.ActionListener;
 import gui.src.menubar.Menu;
 import gui.src.menubar.menuItems.HelpMenuItemFactory;
 
-public class HelpMenuFactory {
+public final class HelpMenuFactory {
 
 
     public static Menu createHelpMenu() {

src/main/java/gui/src/menubar/menus/LanguageMenuFactory.java

@@ -12,7 +12,7 @@ import gui.src.menubar.Menu;
 import gui.src.menubar.MenuBarLanguageController;
 import gui.src.menubar.menuItems.LanguageMenuItemFactory;
 
-public class LanguageMenuFactory {
+public final class LanguageMenuFactory {
 
     public static Menu createLanguageMenu(MenuBarLanguageController languageController) {
         final String[] translations = {"Sprache", "Language"};

src/main/java/gui/src/panels/ControllingPanel.java

@@ -7,7 +7,7 @@ package gui.src.panels;
 
 import javax.swing.JPanel;
 
-public class ControllingPanel extends JPanel {
+public final class ControllingPanel extends JPanel {
     private static ControllingPanel instance;
 
     private ControllingPanel() {

src/main/java/gui/src/panels/MonitoringPanel.java

@@ -7,7 +7,7 @@ package gui.src.panels;
 
 import javax.swing.JPanel;
 
-public class MonitoringPanel extends JPanel {
+public final class MonitoringPanel extends JPanel {
 
     private static MonitoringPanel instance;
 

src/main/java/main/src/Main.java

@@ -7,7 +7,7 @@ package main.src;
 
 import gui.src.frames.MainFrame;
 
-public class Main {
+public final class Main {
     public static void main(String[] args) {
         System.out.println("Hello world!");
         MainFrame.getInstance();