Remove unnecessary modifiers

Change-Id: I890c9b33ae8e8402520230860fa575a9ec757b2d
diff --git a/core/api/src/main/java/org/onosproject/core/MetricsHelper.java b/core/api/src/main/java/org/onosproject/core/MetricsHelper.java
index b5be094..8de0543 100644
--- a/core/api/src/main/java/org/onosproject/core/MetricsHelper.java
+++ b/core/api/src/main/java/org/onosproject/core/MetricsHelper.java
@@ -32,7 +32,7 @@
      *
      * @return MetricService instance
      */
-    abstract MetricsService metricsService();
+    MetricsService metricsService();
 
 
     /**