Fix Javadoc warning

Change-Id: Idb0fb76006cb48a79598ef88eeffa499cc6d4e9a
diff --git a/core/api/src/main/java/org/onosproject/net/newresource/Resource.java b/core/api/src/main/java/org/onosproject/net/newresource/Resource.java
index a2b539e..da80f77 100644
--- a/core/api/src/main/java/org/onosproject/net/newresource/Resource.java
+++ b/core/api/src/main/java/org/onosproject/net/newresource/Resource.java
@@ -114,6 +114,7 @@
     /**
      * Returns the volume of this resource.
      *
+     * @param <T> type of return value
      * @return the volume of this resource
      */
     // TODO: think about other naming possibilities. amount? quantity?