ONOS-3387 Adding ability for network configurations to be validated before being accepted into the system.

Change-Id: I26a7e2adb20318cf17a35081ff753b3448105e31
diff --git a/core/api/src/main/java/org/onosproject/net/config/NetworkConfigService.java b/core/api/src/main/java/org/onosproject/net/config/NetworkConfigService.java
index 8eb69a45..f1b22c4 100644
--- a/core/api/src/main/java/org/onosproject/net/config/NetworkConfigService.java
+++ b/core/api/src/main/java/org/onosproject/net/config/NetworkConfigService.java
@@ -119,7 +119,7 @@
 
     /**
      * Applies configuration for the specified subject and configuration
-     * class using the raw JSON object. If configuration already exists, it
+     * class using the raw JSON node. If configuration already exists, it
      * will be updated.
      *
      * @param subject     configuration subject
@@ -128,6 +128,8 @@
      * @param <S>         type of subject
      * @param <C>         type of configuration
      * @return configuration or null if one is not available
+     * @throws IllegalArgumentException if the supplied JSON node contains
+     *                                  invalid data
      */
     <S, C extends Config<S>> C applyConfig(S subject, Class<C> configClass,
                                            JsonNode json);