diff --git a/integration-test/src/test/java/org/bitcoinj/testing/TestWithNetworkConnections.java b/integration-test/src/test/java/org/bitcoinj/testing/TestWithNetworkConnections.java
index d5c56d22f..390f00895 100644
--- a/integration-test/src/test/java/org/bitcoinj/testing/TestWithNetworkConnections.java
+++ b/integration-test/src/test/java/org/bitcoinj/testing/TestWithNetworkConnections.java
@@ -79,7 +79,7 @@ public class TestWithNetworkConnections {
     protected Address address;
     protected SocketAddress socketAddress;
 
-    private NioServer[] peerServers = new NioServer[PEER_SERVERS];
+    private final NioServer[] peerServers = new NioServer[PEER_SERVERS];
     private final ClientConnectionManager channels;
     protected final BlockingQueue<InboundMessageQueuer> newPeerWriteTargetQueue = new LinkedBlockingQueue<>();