Make Logger instance final as SL4J suggests
diff --git a/src/main/java/net/floodlightcontroller/topology/TopologyManager.java b/src/main/java/net/floodlightcontroller/topology/TopologyManager.java
index a47a5f2..3e624e7 100644
--- a/src/main/java/net/floodlightcontroller/topology/TopologyManager.java
+++ b/src/main/java/net/floodlightcontroller/topology/TopologyManager.java
@@ -61,7 +61,7 @@
         IRoutingService, ILinkDiscoveryListener,
         IOFMessageListener, IHAListener {
 
-    protected static Logger log = LoggerFactory.getLogger(TopologyManager.class);
+    protected final static Logger log = LoggerFactory.getLogger(TopologyManager.class);
 
     public static final String CONTEXT_TUNNEL_ENABLED = 
             "com.bigswitch.floodlight.topologymanager.tunnelEnabled";