Make Logger instance final as SL4J suggests
diff --git a/src/main/java/net/floodlightcontroller/devicemanager/internal/DeviceManagerImpl.java b/src/main/java/net/floodlightcontroller/devicemanager/internal/DeviceManagerImpl.java
index 04543ac..031a528 100755
--- a/src/main/java/net/floodlightcontroller/devicemanager/internal/DeviceManagerImpl.java
+++ b/src/main/java/net/floodlightcontroller/devicemanager/internal/DeviceManagerImpl.java
@@ -91,7 +91,7 @@
 IDeviceService, IOFMessageListener, ITopologyListener,
 IFloodlightModule, IEntityClassListener,
 IFlowReconcileListener, IInfoProvider, IHAListener {
-    protected static Logger logger =
+    protected final static Logger logger =
             LoggerFactory.getLogger(DeviceManagerImpl.class);
 
     protected IFloodlightProviderService floodlightProvider;