Make Logger instance final as SL4J suggests
diff --git a/src/main/java/net/floodlightcontroller/core/util/SingletonTask.java b/src/main/java/net/floodlightcontroller/core/util/SingletonTask.java
index 07729e5..0e03144 100644
--- a/src/main/java/net/floodlightcontroller/core/util/SingletonTask.java
+++ b/src/main/java/net/floodlightcontroller/core/util/SingletonTask.java
@@ -37,7 +37,7 @@
  * * If the task has begun, set a bit to restart it after the current task finishes
  */
 public class SingletonTask {
-    protected static Logger logger = LoggerFactory.getLogger(SingletonTask.class);
+    protected final static Logger logger = LoggerFactory.getLogger(SingletonTask.class);
             
     protected static class SingletonTaskContext  {
         protected boolean taskShouldRun = false;