Make Logger instance final as SL4J suggests
diff --git a/src/main/java/net/floodlightcontroller/core/internal/RoleChanger.java b/src/main/java/net/floodlightcontroller/core/internal/RoleChanger.java
index 4924fbc..194935c 100644
--- a/src/main/java/net/floodlightcontroller/core/internal/RoleChanger.java
+++ b/src/main/java/net/floodlightcontroller/core/internal/RoleChanger.java
@@ -120,7 +120,7 @@
     protected Thread workerThread;
     protected long timeout;
     protected static long DEFAULT_TIMEOUT = 15L*1000*1000*1000L; // 15s
-    protected static Logger log = LoggerFactory.getLogger(RoleChanger.class);
+    protected final static Logger log = LoggerFactory.getLogger(RoleChanger.class);
     /** 
      * A queued task to be handled by the Role changer thread. 
      */