removing possible null pointer exception

Change-Id: I4f8c9393e15d49472ca0f6ce8152d1eb69d886d6
diff --git a/apps/yms/app/src/main/java/org/onosproject/yms/app/yob/YobUtils.java b/apps/yms/app/src/main/java/org/onosproject/yms/app/yob/YobUtils.java
index 76339b8..749a801 100644
--- a/apps/yms/app/src/main/java/org/onosproject/yms/app/yob/YobUtils.java
+++ b/apps/yms/app/src/main/java/org/onosproject/yms/app/yob/YobUtils.java
@@ -673,7 +673,7 @@
         } catch (ClassNotFoundException e) {
             log.error(E_FAIL_TO_LOAD_CLASS, className);
             throw new YobException(E_FAIL_TO_LOAD_CLASS +
-                                           eventSubjectClass.getName());
+                                           qualName);
         } catch (InstantiationException e) {
             log.error(E_FAIL_TO_CREATE_OBJ, className);
             throw new YobException(E_FAIL_TO_CREATE_OBJ +