Make Logger instance final as SL4J suggests
diff --git a/src/test/java/net/onrc/onos/ofcontroller/core/internal/TestableGraphDBOperation.java b/src/test/java/net/onrc/onos/ofcontroller/core/internal/TestableGraphDBOperation.java
index c695f8d..385b49d 100644
--- a/src/test/java/net/onrc/onos/ofcontroller/core/internal/TestableGraphDBOperation.java
+++ b/src/test/java/net/onrc/onos/ofcontroller/core/internal/TestableGraphDBOperation.java
@@ -32,7 +32,7 @@
  *
  */
 public class TestableGraphDBOperation extends GraphDBOperation {
-	protected static Logger log = LoggerFactory.getLogger(TestableGraphDBOperation.class);
+	protected final static Logger log = LoggerFactory.getLogger(TestableGraphDBOperation.class);
 
 	protected List<TestSwitchObject> switches;
 	protected List<TestPortObject> ports;