Make Logger instance final as SL4J suggests
diff --git a/src/main/java/net/onrc/onos/registry/controller/ControllerRegistryResource.java b/src/main/java/net/onrc/onos/registry/controller/ControllerRegistryResource.java
index 51f1d32..8660688 100644
--- a/src/main/java/net/onrc/onos/registry/controller/ControllerRegistryResource.java
+++ b/src/main/java/net/onrc/onos/registry/controller/ControllerRegistryResource.java
@@ -10,7 +10,7 @@
 
 public class ControllerRegistryResource extends ServerResource {
 
-	protected static Logger log = LoggerFactory.getLogger(ControllerRegistryResource.class);
+	protected final static Logger log = LoggerFactory.getLogger(ControllerRegistryResource.class);
 
 	@Get("json")
 	public Collection<String> getControllers() {
diff --git a/src/main/java/net/onrc/onos/registry/controller/StandaloneRegistry.java b/src/main/java/net/onrc/onos/registry/controller/StandaloneRegistry.java
index 640a49d..b6d980a 100644
--- a/src/main/java/net/onrc/onos/registry/controller/StandaloneRegistry.java
+++ b/src/main/java/net/onrc/onos/registry/controller/StandaloneRegistry.java
@@ -25,7 +25,7 @@
  */
 public class StandaloneRegistry implements IFloodlightModule,
 		IControllerRegistryService {
-	protected static Logger log = LoggerFactory.getLogger(StandaloneRegistry.class);
+	protected final static Logger log = LoggerFactory.getLogger(StandaloneRegistry.class);
 	
 	protected IRestApiService restApi;
 	
diff --git a/src/main/java/net/onrc/onos/registry/controller/ZookeeperRegistry.java b/src/main/java/net/onrc/onos/registry/controller/ZookeeperRegistry.java
index 2d2083f..50ee137 100644
--- a/src/main/java/net/onrc/onos/registry/controller/ZookeeperRegistry.java
+++ b/src/main/java/net/onrc/onos/registry/controller/ZookeeperRegistry.java
@@ -49,7 +49,7 @@
  */
 public class ZookeeperRegistry implements IFloodlightModule, IControllerRegistryService {
 
-	protected static Logger log = LoggerFactory.getLogger(ZookeeperRegistry.class);
+	protected final static Logger log = LoggerFactory.getLogger(ZookeeperRegistry.class);
 	protected String controllerId = null;
 	
 	protected IRestApiService restApi;