From 281c29ff6070e08743ee96b0f7ce916bb1c3bba5 Mon Sep 17 00:00:00 2001
From: Apekshit Sharma <appy@apache.org>
Date: Fri, 6 Apr 2018 20:24:45 -0700
Subject: [PATCH] HBASE-20350 NullPointerException in Scanner during close()

---
 .../org/apache/hadoop/hbase/regionserver/KeyValueHeap.java    | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/KeyValueHeap.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/KeyValueHeap.java
index 053ae997c74..b0f42d7e1f3 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/KeyValueHeap.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/KeyValueHeap.java
@@ -224,8 +224,8 @@ public class KeyValueHeap extends NonReversedNonLazyKeyValueScanner
       this.current.close();
     }
     if (this.heap != null) {
-      KeyValueScanner scanner;
-      while ((scanner = this.heap.poll()) != null) {
+      // Order of closing the scanners shouldn't matter here, so simply iterate and close them.
+      for (KeyValueScanner scanner : heap) {
         scanner.close();
       }
     }