diff --git a/src/main/java/org/littleshoot/proxy/impl/DefaultHttpProxyServer.java b/src/main/java/org/littleshoot/proxy/impl/DefaultHttpProxyServer.java
index bda1d5748..4262bc312 100644
--- a/src/main/java/org/littleshoot/proxy/impl/DefaultHttpProxyServer.java
+++ b/src/main/java/org/littleshoot/proxy/impl/DefaultHttpProxyServer.java
@@ -114,9 +114,9 @@ public class DefaultHttpProxyServer implements HttpProxyServer {
     private volatile int idleConnectionTimeout;
     private final HostResolver serverResolver;
     private volatile GlobalTrafficShapingHandler globalTrafficShapingHandler;
-    private int maxInitialLineLength;
-    private int maxHeaderSize;
-    private int maxChunkSize;
+    private final int maxInitialLineLength;
+    private final int maxHeaderSize;
+    private final int maxChunkSize;
 
     /**
      * The alias or pseudonym for this proxy, used when adding the Via header.