[SPARK-15603][MLLIB] Replace SQLContext with SparkSession in ML/MLLib

## What changes were proposed in this pull request?

This PR replaces all deprecated `SQLContext` occurrences with `SparkSession` in `ML/MLLib` module except the following two classes. These two classes use `SQLContext` in their function signatures.
- ReadWrite.scala
- TreeModels.scala

## How was this patch tested?

Pass the existing Jenkins tests.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #13352 from dongjoon-hyun/SPARK-15603.

2 files changed, 10 insertions, 10 deletions

diff --git a/mllib/src/test/scala/org/apache/spark/ml/feature/QuantileDiscretizerSuite.scala b/mllib/src/test/scala/org/apache/spark/ml/feature/QuantileDiscretizerSuite.scala
index 8895d630a0..621c13a8e5 100644
--- a/mllib/src/test/scala/org/apache/spark/ml/feature/QuantileDiscretizerSuite.scala
+++ b/mllib/src/test/scala/org/apache/spark/ml/feature/QuantileDiscretizerSuite.scala
@@ -20,15 +20,15 @@ package org.apache.spark.ml.feature
 import org.apache.spark.SparkFunSuite
 import org.apache.spark.ml.util.DefaultReadWriteTest
 import org.apache.spark.mllib.util.MLlibTestSparkContext
-import org.apache.spark.sql.SQLContext
+import org.apache.spark.sql.SparkSession
 import org.apache.spark.sql.functions.udf
 
 class QuantileDiscretizerSuite
   extends SparkFunSuite with MLlibTestSparkContext with DefaultReadWriteTest {
 
   test("Test observed number of buckets and their sizes match expected values") {
-    val sqlCtx = SQLContext.getOrCreate(sc)
-    import sqlCtx.implicits._
+    val spark = SparkSession.builder().config(sc.getConf).getOrCreate()
+    import spark.implicits._
 
     val datasetSize = 100000
     val numBuckets = 5
@@ -53,8 +53,8 @@ class QuantileDiscretizerSuite
   }
 
   test("Test transform method on unseen data") {
-    val sqlCtx = SQLContext.getOrCreate(sc)
-    import sqlCtx.implicits._
+    val spark = SparkSession.builder().config(sc.getConf).getOrCreate()
+    import spark.implicits._
 
     val trainDF = sc.parallelize(1.0 to 100.0 by 1.0).map(Tuple1.apply).toDF("input")
     val testDF = sc.parallelize(-10.0 to 110.0 by 1.0).map(Tuple1.apply).toDF("input")
@@ -82,8 +82,8 @@ class QuantileDiscretizerSuite
   }
 
   test("Verify resulting model has parent") {
-    val sqlCtx = SQLContext.getOrCreate(sc)
-    import sqlCtx.implicits._
+    val spark = SparkSession.builder().config(sc.getConf).getOrCreate()
+    import spark.implicits._
 
     val df = sc.parallelize(1 to 100).map(Tuple1.apply).toDF("input")
     val discretizer = new QuantileDiscretizer()
diff --git a/mllib/src/test/scala/org/apache/spark/mllib/util/MLlibTestSparkContext.scala b/mllib/src/test/scala/org/apache/spark/mllib/util/MLlibTestSparkContext.scala
index ba8d36f45f..db56aff631 100644
--- a/mllib/src/test/scala/org/apache/spark/mllib/util/MLlibTestSparkContext.scala
+++ b/mllib/src/test/scala/org/apache/spark/mllib/util/MLlibTestSparkContext.scala
@@ -21,9 +21,9 @@ import java.io.File
 
 import org.scalatest.Suite
 
-import org.apache.spark.{SparkConf, SparkContext}
+import org.apache.spark.SparkContext
 import org.apache.spark.ml.util.TempDirectory
-import org.apache.spark.sql.{SparkSession, SQLContext}
+import org.apache.spark.sql.SparkSession
 import org.apache.spark.util.Utils
 
 trait MLlibTestSparkContext extends TempDirectory { self: Suite =>
@@ -46,7 +46,7 @@ trait MLlibTestSparkContext extends TempDirectory { self: Suite =>
   override def afterAll() {
     try {
       Utils.deleteRecursively(new File(checkpointDir))
-      SQLContext.clearActive()
+      SparkSession.clearActiveSession()
       if (spark != null) {
         spark.stop()
       }