From 86e47ce3469929b8086923fe3d201f9db2b2da83 Mon Sep 17 00:00:00 2001
From: Dongjoon Hyun <dongjoon@apache.org>
Date: Wed, 5 Jul 2017 23:10:20 -0700
Subject: [PATCH] [TEST][TEST-MAVEN] createSparkSession should be synchronized

---
 .../scala/org/apache/spark/sql/test/SharedSQLContext.scala  | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/sql/core/src/test/scala/org/apache/spark/sql/test/SharedSQLContext.scala b/sql/core/src/test/scala/org/apache/spark/sql/test/SharedSQLContext.scala
index 7cea4c02155ea..eb387ebfefc2e 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/test/SharedSQLContext.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/test/SharedSQLContext.scala
@@ -61,8 +61,10 @@ trait SharedSQLContext extends SQLTestUtils with BeforeAndAfterEach with Eventua
    */
   protected override def beforeAll(): Unit = {
     SparkSession.sqlListener.set(null)
-    if (_spark == null) {
-      _spark = createSparkSession
+    synchronized {
+      if (_spark == null) {
+        _spark = createSparkSession
+      }
     }
     // Ensure we have initialized the context before calling parent code
     super.beforeAll()