diff --git a/core/src/test/scala/org/apache/spark/rdd/DoubleRDDSuite.scala b/core/src/test/scala/org/apache/spark/rdd/DoubleRDDSuite.scala
index 071084485a..0d8ac19024 100644
--- a/core/src/test/scala/org/apache/spark/rdd/DoubleRDDSuite.scala
+++ b/core/src/test/scala/org/apache/spark/rdd/DoubleRDDSuite.scala
@@ -32,154 +32,154 @@ class DoubleRDDSuite extends FunSuite with SharedSparkContext {
   test("WorksOnEmpty") {
     // Make sure that it works on an empty input
     val rdd: RDD[Double] = sc.parallelize(Seq())
-    val buckets: Array[Double] = Array(0.0, 10.0)
-    val histogramResults: Array[Long] = rdd.histogram(buckets)
-    val histogramResults2: Array[Long] = rdd.histogram(buckets, true)
-    val expectedHistogramResults: Array[Long] = Array(0)
+    val buckets = Array(0.0, 10.0)
+    val histogramResults = rdd.histogram(buckets)
+    val histogramResults2 = rdd.histogram(buckets, true)
+    val expectedHistogramResults = Array(0)
     assert(histogramResults === expectedHistogramResults)
     assert(histogramResults2 === expectedHistogramResults)
   }
   test("WorksWithOutOfRangeWithOneBucket") {
     // Verify that if all of the elements are out of range the counts are zero
-    val rdd: RDD[Double] = sc.parallelize(Seq(10.01, -0.01))
-    val buckets: Array[Double] = Array(0.0, 10.0)
-    val histogramResults: Array[Long] = rdd.histogram(buckets)
-    val histogramResults2: Array[Long] = rdd.histogram(buckets, true)
-    val expectedHistogramResults: Array[Long] = Array(0)
+    val rdd = sc.parallelize(Seq(10.01, -0.01))
+    val buckets = Array(0.0, 10.0)
+    val histogramResults = rdd.histogram(buckets)
+    val histogramResults2 = rdd.histogram(buckets, true)
+    val expectedHistogramResults = Array(0)
     assert(histogramResults === expectedHistogramResults)
     assert(histogramResults2 === expectedHistogramResults)
   }
   test("WorksInRangeWithOneBucket") {
     // Verify the basic case of one bucket and all elements in that bucket works
-    val rdd: RDD[Double] = sc.parallelize(Seq(1, 2, 3, 4))
-    val buckets: Array[Double] = Array(0.0, 10.0)
-    val histogramResults: Array[Long] = rdd.histogram(buckets)
-    val histogramResults2: Array[Long] = rdd.histogram(buckets, true)
-    val expectedHistogramResults: Array[Long] = Array(4)
+    val rdd = sc.parallelize(Seq(1, 2, 3, 4))
+    val buckets = Array(0.0, 10.0)
+    val histogramResults = rdd.histogram(buckets)
+    val histogramResults2 = rdd.histogram(buckets, true)
+    val expectedHistogramResults = Array(4)
     assert(histogramResults === expectedHistogramResults)
     assert(histogramResults2 === expectedHistogramResults)
   }
   test("WorksInRangeWithOneBucketExactMatch") {
     // Verify the basic case of one bucket and all elements in that bucket works
-    val rdd: RDD[Double] = sc.parallelize(Seq(1, 2, 3, 4))
-    val buckets: Array[Double] = Array(1.0, 4.0)
-    val histogramResults: Array[Long] = rdd.histogram(buckets)
-    val histogramResults2: Array[Long] = rdd.histogram(buckets, true)
-    val expectedHistogramResults: Array[Long] = Array(4)
+    val rdd = sc.parallelize(Seq(1, 2, 3, 4))
+    val buckets = Array(1.0, 4.0)
+    val histogramResults = rdd.histogram(buckets)
+    val histogramResults2 = rdd.histogram(buckets, true)
+    val expectedHistogramResults = Array(4)
     assert(histogramResults === expectedHistogramResults)
     assert(histogramResults2 === expectedHistogramResults)
   }
   test("WorksWithOutOfRangeWithTwoBuckets") {
     // Verify that out of range works with two buckets
-    val rdd: RDD[Double] = sc.parallelize(Seq(10.01, -0.01))
-    val buckets: Array[Double] = Array(0.0, 5.0, 10.0)
-    val histogramResults: Array[Long] = rdd.histogram(buckets)
-    val histogramResults2: Array[Long] = rdd.histogram(buckets, true)
-    val expectedHistogramResults: Array[Long] = Array(0, 0)
+    val rdd = sc.parallelize(Seq(10.01, -0.01))
+    val buckets = Array(0.0, 5.0, 10.0)
+    val histogramResults = rdd.histogram(buckets)
+    val histogramResults2 = rdd.histogram(buckets, true)
+    val expectedHistogramResults = Array(0, 0)
     assert(histogramResults === expectedHistogramResults)
     assert(histogramResults2 === expectedHistogramResults)
   }
   test("WorksWithOutOfRangeWithTwoUnEvenBuckets") {
     // Verify that out of range works with two un even buckets
-    val rdd: RDD[Double] = sc.parallelize(Seq(10.01, -0.01))
-    val buckets: Array[Double] = Array(0.0, 4.0, 10.0)
-    val histogramResults: Array[Long] = rdd.histogram(buckets)
-    val expectedHistogramResults: Array[Long] = Array(0, 0)
+    val rdd = sc.parallelize(Seq(10.01, -0.01))
+    val buckets = Array(0.0, 4.0, 10.0)
+    val histogramResults = rdd.histogram(buckets)
+    val expectedHistogramResults = Array(0, 0)
     assert(histogramResults === expectedHistogramResults)
   }
   test("WorksInRangeWithTwoBuckets") {
     // Make sure that it works with two equally spaced buckets and elements in each
-    val rdd: RDD[Double] = sc.parallelize(Seq(1, 2, 3, 5, 6))
-    val buckets: Array[Double] = Array(0.0, 5.0, 10.0)
-    val histogramResults: Array[Long] = rdd.histogram(buckets)
-    val histogramResults2: Array[Long] = rdd.histogram(buckets, true)
-    val expectedHistogramResults: Array[Long] = Array(3, 2)
+    val rdd = sc.parallelize(Seq(1, 2, 3, 5, 6))
+    val buckets = Array(0.0, 5.0, 10.0)
+    val histogramResults = rdd.histogram(buckets)
+    val histogramResults2 = rdd.histogram(buckets, true)
+    val expectedHistogramResults = Array(3, 2)
     assert(histogramResults === expectedHistogramResults)
     assert(histogramResults2 === expectedHistogramResults)
   }
   test("WorksInRangeWithTwoBucketsAndNaN") {
     // Make sure that it works with two equally spaced buckets and elements in each
-    val rdd: RDD[Double] = sc.parallelize(Seq(1, 2, 3, 5, 6, Double.NaN))
-    val buckets: Array[Double] = Array(0.0, 5.0, 10.0)
-    val histogramResults: Array[Long] = rdd.histogram(buckets)
-    val histogramResults2: Array[Long] = rdd.histogram(buckets, true)
-    val expectedHistogramResults: Array[Long] = Array(3, 2)
+    val rdd = sc.parallelize(Seq(1, 2, 3, 5, 6, Double.NaN))
+    val buckets = Array(0.0, 5.0, 10.0)
+    val histogramResults = rdd.histogram(buckets)
+    val histogramResults2 = rdd.histogram(buckets, true)
+    val expectedHistogramResults = Array(3, 2)
     assert(histogramResults === expectedHistogramResults)
     assert(histogramResults2 === expectedHistogramResults)
   }
   test("WorksInRangeWithTwoUnevenBuckets") {
     // Make sure that it works with two unequally spaced buckets and elements in each
-    val rdd: RDD[Double] = sc.parallelize(Seq(1, 2, 3, 5, 6))
-    val buckets: Array[Double] = Array(0.0, 5.0, 11.0)
-    val histogramResults: Array[Long] = rdd.histogram(buckets)
-    val expectedHistogramResults: Array[Long] = Array(3, 2)
+    val rdd = sc.parallelize(Seq(1, 2, 3, 5, 6))
+    val buckets = Array(0.0, 5.0, 11.0)
+    val histogramResults = rdd.histogram(buckets)
+    val expectedHistogramResults = Array(3, 2)
     assert(histogramResults === expectedHistogramResults)
   }
   test("WorksMixedRangeWithTwoUnevenBuckets") {
     // Make sure that it works with two unequally spaced buckets and elements in each
-    val rdd: RDD[Double] = sc.parallelize(Seq(-0.01, 0.0, 1, 2, 3, 5, 6, 11.0, 11.01))
-    val buckets: Array[Double] = Array(0.0, 5.0, 11.0)
-    val histogramResults: Array[Long] = rdd.histogram(buckets)
-    val expectedHistogramResults: Array[Long] = Array(4, 3)
+    val rdd = sc.parallelize(Seq(-0.01, 0.0, 1, 2, 3, 5, 6, 11.0, 11.01))
+    val buckets = Array(0.0, 5.0, 11.0)
+    val histogramResults = rdd.histogram(buckets)
+    val expectedHistogramResults = Array(4, 3)
     assert(histogramResults === expectedHistogramResults)
   }
   test("WorksMixedRangeWithFourUnevenBuckets") {
     // Make sure that it works with two unequally spaced buckets and elements in each
-    val rdd: RDD[Double] = sc.parallelize(Seq(-0.01, 0.0, 1, 2, 3, 5, 6, 11.01, 12.0, 199.0,
+    val rdd = sc.parallelize(Seq(-0.01, 0.0, 1, 2, 3, 5, 6, 11.01, 12.0, 199.0,
       200.0, 200.1))
-    val buckets: Array[Double] = Array(0.0, 5.0, 11.0, 12.0, 200.0)
-    val histogramResults: Array[Long] = rdd.histogram(buckets)
-    val expectedHistogramResults: Array[Long] = Array(4, 2, 1, 3)
+    val buckets = Array(0.0, 5.0, 11.0, 12.0, 200.0)
+    val histogramResults = rdd.histogram(buckets)
+    val expectedHistogramResults = Array(4, 2, 1, 3)
     assert(histogramResults === expectedHistogramResults)
   }
   test("WorksMixedRangeWithUnevenBucketsAndNaN") {
     // Make sure that it works with two unequally spaced buckets and elements in each
-    val rdd: RDD[Double] = sc.parallelize(Seq(-0.01, 0.0, 1, 2, 3, 5, 6, 11.01, 12.0, 199.0,
+    val rdd = sc.parallelize(Seq(-0.01, 0.0, 1, 2, 3, 5, 6, 11.01, 12.0, 199.0,
       200.0, 200.1, Double.NaN))
-    val buckets: Array[Double] = Array(0.0, 5.0, 11.0, 12.0, 200.0)
-    val histogramResults: Array[Long] = rdd.histogram(buckets)
-    val expectedHistogramResults: Array[Long] = Array(4, 2, 1, 3)
+    val buckets = Array(0.0, 5.0, 11.0, 12.0, 200.0)
+    val histogramResults = rdd.histogram(buckets)
+    val expectedHistogramResults = Array(4, 2, 1, 3)
     assert(histogramResults === expectedHistogramResults)
   }
   // Make sure this works with a NaN end bucket
   test("WorksMixedRangeWithUnevenBucketsAndNaNAndNaNRange") {
     // Make sure that it works with two unequally spaced buckets and elements in each
-    val rdd: RDD[Double] = sc.parallelize(Seq(-0.01, 0.0, 1, 2, 3, 5, 6, 11.01, 12.0, 199.0,
+    val rdd = sc.parallelize(Seq(-0.01, 0.0, 1, 2, 3, 5, 6, 11.01, 12.0, 199.0,
       200.0, 200.1, Double.NaN))
-    val buckets: Array[Double] = Array(0.0, 5.0, 11.0, 12.0, 200.0, Double.NaN)
-    val histogramResults: Array[Long] = rdd.histogram(buckets)
-    val expectedHistogramResults: Array[Long] = Array(4, 2, 1, 2, 3)
+    val buckets = Array(0.0, 5.0, 11.0, 12.0, 200.0, Double.NaN)
+    val histogramResults = rdd.histogram(buckets)
+    val expectedHistogramResults = Array(4, 2, 1, 2, 3)
     assert(histogramResults === expectedHistogramResults)
   }
   // Make sure this works with a NaN end bucket and an inifity
   test("WorksMixedRangeWithUnevenBucketsAndNaNAndNaNRangeAndInfity") {
     // Make sure that it works with two unequally spaced buckets and elements in each
-    val rdd: RDD[Double] = sc.parallelize(Seq(-0.01, 0.0, 1, 2, 3, 5, 6, 11.01, 12.0, 199.0,
+    val rdd = sc.parallelize(Seq(-0.01, 0.0, 1, 2, 3, 5, 6, 11.01, 12.0, 199.0,
       200.0, 200.1, 1.0/0.0, -1.0/0.0, Double.NaN))
-    val buckets: Array[Double] = Array(0.0, 5.0, 11.0, 12.0, 200.0, Double.NaN)
-    val histogramResults: Array[Long] = rdd.histogram(buckets)
-    val expectedHistogramResults: Array[Long] = Array(4, 2, 1, 2, 4)
+    val buckets = Array(0.0, 5.0, 11.0, 12.0, 200.0, Double.NaN)
+    val histogramResults = rdd.histogram(buckets)
+    val expectedHistogramResults = Array(4, 2, 1, 2, 4)
     assert(histogramResults === expectedHistogramResults)
   }
   test("WorksWithOutOfRangeWithInfiniteBuckets") {
     // Verify that out of range works with two buckets
-    val rdd: RDD[Double] = sc.parallelize(Seq(10.01, -0.01, Double.NaN))
-    val buckets: Array[Double] = Array(-1.0/0.0 , 0.0, 1.0/0.0)
-    val histogramResults: Array[Long] = rdd.histogram(buckets)
-    val expectedHistogramResults: Array[Long] = Array(1, 1)
+    val rdd = sc.parallelize(Seq(10.01, -0.01, Double.NaN))
+    val buckets = Array(-1.0/0.0 , 0.0, 1.0/0.0)
+    val histogramResults = rdd.histogram(buckets)
+    val expectedHistogramResults = Array(1, 1)
     assert(histogramResults === expectedHistogramResults)
   }
   // Test the failure mode with an invalid bucket array
   test("ThrowsExceptionOnInvalidBucketArray") {
-    val rdd: RDD[Double] = sc.parallelize(Seq(1.0))
+    val rdd = sc.parallelize(Seq(1.0))
     // Empty array
     intercept[IllegalArgumentException] {
-      val buckets: Array[Double] = Array.empty[Double]
+      val buckets = Array.empty[Double]
       val result = rdd.histogram(buckets)
     }
     // Single element array
     intercept[IllegalArgumentException] {
-      val buckets: Array[Double] = Array(1.0)
+      val buckets = Array(1.0)
       val result = rdd.histogram(buckets)
     }
   }
@@ -187,49 +187,49 @@ class DoubleRDDSuite extends FunSuite with SharedSparkContext {
   // Test automatic histogram function
   test("WorksWithoutBucketsBasic") {
     // Verify the basic case of one bucket and all elements in that bucket works
-    val rdd: RDD[Double] = sc.parallelize(Seq(1, 2, 3, 4))
+    val rdd = sc.parallelize(Seq(1, 2, 3, 4))
     val (histogramBuckets, histogramResults) = rdd.histogram(1)
-    val expectedHistogramResults: Array[Long] = Array(4)
-    val expectedHistogramBuckets: Array[Double] = Array(1.0, 4.0)
+    val expectedHistogramResults = Array(4)
+    val expectedHistogramBuckets = Array(1.0, 4.0)
     assert(histogramResults === expectedHistogramResults)
     assert(histogramBuckets === expectedHistogramBuckets)
   }
   // Test automatic histogram function with a single element
   test("WorksWithoutBucketsBasicSingleElement") {
     // Verify the basic case of one bucket and all elements in that bucket works
-    val rdd: RDD[Double] = sc.parallelize(Seq(1))
+    val rdd = sc.parallelize(Seq(1))
     val (histogramBuckets, histogramResults) = rdd.histogram(1)
-    val expectedHistogramResults: Array[Long] = Array(1)
-    val expectedHistogramBuckets: Array[Double] = Array(1.0, 1.0)
+    val expectedHistogramResults = Array(1)
+    val expectedHistogramBuckets = Array(1.0, 1.0)
     assert(histogramResults === expectedHistogramResults)
     assert(histogramBuckets === expectedHistogramBuckets)
   }
   // Test automatic histogram function with a single element
   test("WorksWithoutBucketsBasicNoRange") {
     // Verify the basic case of one bucket and all elements in that bucket works
-    val rdd: RDD[Double] = sc.parallelize(Seq(1, 1, 1, 1))
+    val rdd = sc.parallelize(Seq(1, 1, 1, 1))
     val (histogramBuckets, histogramResults) = rdd.histogram(1)
-    val expectedHistogramResults: Array[Long] = Array(4)
-    val expectedHistogramBuckets: Array[Double] = Array(1.0, 1.0)
+    val expectedHistogramResults = Array(4)
+    val expectedHistogramBuckets = Array(1.0, 1.0)
     assert(histogramResults === expectedHistogramResults)
     assert(histogramBuckets === expectedHistogramBuckets)
   }
   test("WorksWithoutBucketsBasicTwo") {
     // Verify the basic case of one bucket and all elements in that bucket works
-    val rdd: RDD[Double] = sc.parallelize(Seq(1, 2, 3, 4))
+    val rdd = sc.parallelize(Seq(1, 2, 3, 4))
     val (histogramBuckets, histogramResults) = rdd.histogram(2)
-    val expectedHistogramResults: Array[Long] = Array(2, 2)
-    val expectedHistogramBuckets: Array[Double] = Array(1.0, 2.5, 4.0)
+    val expectedHistogramResults = Array(2, 2)
+    val expectedHistogramBuckets = Array(1.0, 2.5, 4.0)
     assert(histogramResults === expectedHistogramResults)
     assert(histogramBuckets === expectedHistogramBuckets)
   }
   test("WorksWithoutBucketsWithMoreRequestedThanElements") {
     // Verify the basic case of one bucket and all elements in that bucket works
-    val rdd: RDD[Double] = sc.parallelize(Seq(1, 2))
+    val rdd = sc.parallelize(Seq(1, 2))
     val (histogramBuckets, histogramResults) = rdd.histogram(10)
-    val expectedHistogramResults: Array[Long] =
+    val expectedHistogramResults =
       Array(1, 0, 0, 0, 0, 0, 0, 0, 0, 1)
-    val expectedHistogramBuckets: Array[Double] =
+    val expectedHistogramBuckets =
       Array(1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0)
     assert(histogramResults === expectedHistogramResults)
     assert(histogramBuckets === expectedHistogramBuckets)
@@ -239,12 +239,12 @@ class DoubleRDDSuite extends FunSuite with SharedSparkContext {
   test("ThrowsExceptionOnInvalidRDDs") {
     // infinity
     intercept[UnsupportedOperationException] {
-      val rdd: RDD[Double] = sc.parallelize(Seq(1, 1.0/0.0))
+      val rdd = sc.parallelize(Seq(1, 1.0/0.0))
       val result = rdd.histogram(1)
     }
     // NaN
     intercept[UnsupportedOperationException] {
-      val rdd: RDD[Double] = sc.parallelize(Seq(1, Double.NaN))
+      val rdd = sc.parallelize(Seq(1, Double.NaN))
       val result = rdd.histogram(1)
     }
     // Empty