diff --git a/core/src/main/scala/org/apache/spark/util/collection/ExternalAppendOnlyMap.scala b/core/src/main/scala/org/apache/spark/util/collection/ExternalAppendOnlyMap.scala
index 375f4a6921225..5c6dd45ec58e3 100644
--- a/core/src/main/scala/org/apache/spark/util/collection/ExternalAppendOnlyMap.scala
+++ b/core/src/main/scala/org/apache/spark/util/collection/ExternalAppendOnlyMap.scala
@@ -463,7 +463,7 @@ class ExternalAppendOnlyMap[K, V, C](
 
     // An intermediate stream that reads from exactly one batch
     // This guards against pre-fetching and other arbitrary behavior of higher level streams
-    private var deserializeStream = nextBatchStream()
+    private var deserializeStream: DeserializationStream = null
     private var nextItem: (K, C) = null
     private var objectsRead = 0
 
@@ -528,7 +528,11 @@ class ExternalAppendOnlyMap[K, V, C](
     override def hasNext: Boolean = {
       if (nextItem == null) {
         if (deserializeStream == null) {
-          return false
+          // In case of deserializeStream has not been initialized
+          deserializeStream = nextBatchStream()
+          if (deserializeStream == null) {
+            return false
+          }
         }
         nextItem = readNextItem()
       }
@@ -536,19 +540,18 @@ class ExternalAppendOnlyMap[K, V, C](
     }
 
     override def next(): (K, C) = {
-      val item = if (nextItem == null) readNextItem() else nextItem
-      if (item == null) {
+      if (!hasNext) {
         throw new NoSuchElementException
       }
+      val item = nextItem
       nextItem = null
       item
     }
 
     private def cleanup() {
       batchIndex = batchOffsets.length  // Prevent reading any other batch
-      val ds = deserializeStream
-      if (ds != null) {
-        ds.close()
+      if (deserializeStream != null) {
+        deserializeStream.close()
         deserializeStream = null
       }
       if (fileStream != null) {