[SPARK-7859] [SQL] Collect_set() behavior differences which fails the unit test under jdk8

To reproduce that:
```
JAVA_HOME=/home/hcheng/Java/jdk1.8.0_45 | build/sbt -Phadoop-2.3 -Phive  'test-only org.apache.spark.sql.hive.execution.HiveWindowFunctionQueryWithoutCodeGenSuite'
```

A simple workaround to fix that is update the original query, for getting the output size instead of the exact elements of the array (output by collect_set())

Author: Cheng Hao <hao.cheng@intel.com>

Closes #6402 from chenghao-intel/windowing and squashes the following commits:

99312ad [Cheng Hao] add order by for the select clause
edf8ce3 [Cheng Hao] update the code as suggested
7062da7 [Cheng Hao] fix the collect_set() behaviour differences under different versions of JDK

1 files changed, 8 insertions, 0 deletions

diff --git a/sql/hive/compatibility/src/test/scala/org/apache/spark/sql/hive/execution/HiveWindowFunctionQuerySuite.scala b/sql/hive/compatibility/src/test/scala/org/apache/spark/sql/hive/execution/HiveWindowFunctionQuerySuite.scala
index 934452fe57..31a49a3683 100644
--- a/sql/hive/compatibility/src/test/scala/org/apache/spark/sql/hive/execution/HiveWindowFunctionQuerySuite.scala
+++ b/sql/hive/compatibility/src/test/scala/org/apache/spark/sql/hive/execution/HiveWindowFunctionQuerySuite.scala
@@ -526,8 +526,14 @@ abstract class HiveWindowFunctionQueryBaseSuite extends HiveComparisonTest with
       |             rows between 2 preceding and 2 following);
     """.stripMargin, reset = false)
 
+  // collect_set() output array in an arbitrary order, hence causes different result
+  // when running this test suite under Java 7 and 8.
+  // We change the original sql query a little bit for making the test suite passed
+  // under different JDK
   createQueryTest("windowing.q -- 20. testSTATs",
     """
+      |select p_mfgr,p_name, p_size, sdev, sdev_pop, uniq_data, var, cor, covarp
+      |from (
       |select  p_mfgr,p_name, p_size,
       |stddev(p_retailprice) over w1 as sdev,
       |stddev_pop(p_retailprice) over w1 as sdev_pop,
@@ -538,6 +544,8 @@ abstract class HiveWindowFunctionQueryBaseSuite extends HiveComparisonTest with
       |from part
       |window w1 as (distribute by p_mfgr sort by p_mfgr, p_name
       |             rows between 2 preceding and 2 following)
+      |) t lateral view explode(uniq_size) d as uniq_data
+      |order by p_mfgr,p_name, p_size, sdev, sdev_pop, uniq_data, var, cor, covarp
     """.stripMargin, reset = false)
 
   createQueryTest("windowing.q -- 21. testDISTs",