Make Logger instance final as SL4J suggests
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