diff --git a/src/main/java/inf112/fiasko/roborally/networking/RoboRallyClient.java b/src/main/java/inf112/fiasko/roborally/networking/RoboRallyClient.java
index 24c4059..a5eb22c 100644
--- a/src/main/java/inf112/fiasko/roborally/networking/RoboRallyClient.java
+++ b/src/main/java/inf112/fiasko/roborally/networking/RoboRallyClient.java
@@ -15,7 +15,7 @@ import java.io.IOException;
  * This class represents a client capable of connecting to a Robo Rally server
  */
 public class RoboRallyClient {
-    private Client client;
+    private final Client client;
 
     /**
      * Instantiates a new Robo Rally client
@@ -45,7 +45,7 @@ public class RoboRallyClient {
  * This listener handles all receiving from the server
  */
 class RoboRallyClientListener extends Listener {
-    private RoboRallyWrapper wrapper;
+    private final RoboRallyWrapper wrapper;
 
     RoboRallyClientListener(RoboRallyWrapper wrapper) {
         super();
diff --git a/src/main/java/inf112/fiasko/roborally/networking/RoboRallyServer.java b/src/main/java/inf112/fiasko/roborally/networking/RoboRallyServer.java
index 020b64f..8c94ba2 100644
--- a/src/main/java/inf112/fiasko/roborally/networking/RoboRallyServer.java
+++ b/src/main/java/inf112/fiasko/roborally/networking/RoboRallyServer.java
@@ -15,7 +15,7 @@ import java.util.Map;
  * This class represents a Robo Rally Server
  */
 public class RoboRallyServer {
-    private Server server;
+    private final Server server;
     private RoboRallyServerListener listener;
 
     public RoboRallyServer() throws IOException {
@@ -56,8 +56,8 @@ public class RoboRallyServer {
  */
 class RoboRallyServerListener extends Listener {
     private Connection host;
-    private Map<Connection, RobotID> clients;
-    private Map<Connection, String> playerNames;
+    private final Map<Connection, RobotID> clients;
+    private final Map<Connection, String> playerNames;
 
     /**
      * Instantiates a new Robo Rally server listener
diff --git a/src/main/java/inf112/fiasko/roborally/networking/containers/ErrorResponse.java b/src/main/java/inf112/fiasko/roborally/networking/containers/ErrorResponse.java
index 3bf7358..3220ba9 100644
--- a/src/main/java/inf112/fiasko/roborally/networking/containers/ErrorResponse.java
+++ b/src/main/java/inf112/fiasko/roborally/networking/containers/ErrorResponse.java
@@ -4,7 +4,7 @@ package inf112.fiasko.roborally.networking.containers;
  * This class represents a response saying that something went wrong with the request
  */
 public class ErrorResponse {
-    private String errorMessage;
+    private final String errorMessage;
     private Exception thrownException;
 
     /**