ONOS-885: Group store interface definition and in-memory store implementation

Change-Id: I1125fbc23f1e58bcb8aaf5f67c02da610fa7ef25

ONOS-885: Group store interface definition and in-memory store implementation

Change-Id: Id3794bed63785e10ed86c0b5d90bf875d127224c
diff --git a/core/api/src/main/java/org/onosproject/net/group/GroupBuckets.java b/core/api/src/main/java/org/onosproject/net/group/GroupBuckets.java
index c4aaad2..10f4eca 100644
--- a/core/api/src/main/java/org/onosproject/net/group/GroupBuckets.java
+++ b/core/api/src/main/java/org/onosproject/net/group/GroupBuckets.java
@@ -19,9 +19,11 @@
 
 import java.util.List;
 
-
 import com.google.common.collect.ImmutableList;
 
+/**
+ * Immutable collection of group bucket.
+ */
 public final class GroupBuckets {
     private final List<GroupBucket> buckets;
 
@@ -35,7 +37,7 @@
     }
 
     /**
-     * Immutable list of group buckets.
+     * Returns immutable list of group buckets.
      *
      * @return list of group bucket
      */