diff --git a/CHANGES.txt b/CHANGES.txt
index c349c433b8f..fc9238670e8 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -68,6 +68,9 @@ Release 0.21.0 - Unreleased
    HBASE-1906  FilterList of prefix and columnvalue not working properly with
                deletes and multiple values
    HBASE-1896  WhileMatchFilter.reset should call encapsulated filter reset
+   HBASE-1912  When adding a secondary index to an existing table, it will
+               cause NPE during re-indexing (Mingjui Ray Liao via Andrew
+               Purtell)
 
   IMPROVEMENTS
    HBASE-1760  Cleanup TODOs in HTable
diff --git a/src/contrib/transactional/src/java/org/apache/hadoop/hbase/client/tableindexed/IndexSpecification.java b/src/contrib/transactional/src/java/org/apache/hadoop/hbase/client/tableindexed/IndexSpecification.java
index 552d83dfaab..b1c0a8738a7 100644
--- a/src/contrib/transactional/src/java/org/apache/hadoop/hbase/client/tableindexed/IndexSpecification.java
+++ b/src/contrib/transactional/src/java/org/apache/hadoop/hbase/client/tableindexed/IndexSpecification.java
@@ -78,9 +78,10 @@ public class IndexSpecification implements Writable {
       byte[][] additionalColumns, IndexKeyGenerator keyGenerator) {
     this.indexId = indexId;
     this.indexedColumns = indexedColumns;
-    this.additionalColumns = additionalColumns;
     this.keyGenerator = keyGenerator;
     this.makeAllColumns();
+    this.additionalColumns = (additionalColumns == null)? new byte[0][0] :
+                                                          additionalColumns;
   }
 
   public IndexSpecification() {