Pull up components() method as an abstract method

Change-Id: I80aecb74958b697fb18336bbe39853dd5cb67578
diff --git a/core/api/src/main/java/org/onosproject/net/newresource/DiscreteResourceId.java b/core/api/src/main/java/org/onosproject/net/newresource/DiscreteResourceId.java
index 4b83344..3e5fc93 100644
--- a/core/api/src/main/java/org/onosproject/net/newresource/DiscreteResourceId.java
+++ b/core/api/src/main/java/org/onosproject/net/newresource/DiscreteResourceId.java
@@ -42,6 +42,7 @@
         this.components = ImmutableList.of();
     }
 
+    @Override
     ImmutableList<Object> components() {
         return components;
     }