Make Logger instance final as SL4J suggests
diff --git a/src/main/java/net/floodlightcontroller/devicemanager/internal/Device.java b/src/main/java/net/floodlightcontroller/devicemanager/internal/Device.java
index 645125e..05ebcf3 100755
--- a/src/main/java/net/floodlightcontroller/devicemanager/internal/Device.java
+++ b/src/main/java/net/floodlightcontroller/devicemanager/internal/Device.java
@@ -50,7 +50,7 @@
  */
 @JsonSerialize(using=DeviceSerializer.class)
 public class Device implements IDevice {
-    protected static Logger log =
+    protected final static Logger log =
             LoggerFactory.getLogger(Device.class);
 
     protected Long deviceKey;
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;
diff --git a/src/main/java/net/floodlightcontroller/devicemanager/internal/IndexedEntity.java b/src/main/java/net/floodlightcontroller/devicemanager/internal/IndexedEntity.java
index 3e0829d..3bb9bfa 100644
--- a/src/main/java/net/floodlightcontroller/devicemanager/internal/IndexedEntity.java
+++ b/src/main/java/net/floodlightcontroller/devicemanager/internal/IndexedEntity.java
@@ -19,7 +19,7 @@
     protected EnumSet<DeviceField> keyFields;
     protected Entity entity;
     private int hashCode = 0;
-    protected static Logger logger =
+    protected final static Logger logger =
             LoggerFactory.getLogger(IndexedEntity.class);
     /**
      * Create a new {@link IndexedEntity} for the given {@link Entity} using