Remove explicit boxing

core/src/main/scala/org/apache/spark/api/java/JavaDoubleRDD.scala

@@ -169,9 +169,9 @@ class JavaDoubleRDD(val srdd: RDD[scala.Double]) extends JavaRDDLike[Double, Jav
    * If the RDD contains infinity, NaN throws an exception
    * If the elements in RDD do not vary (max == min) always returns a single bucket.
    */
-  def histogram(bucketCount: Int): Pair[Array[Double], Array[Long]] = {
+  def histogram(bucketCount: Int): Pair[Array[scala.Double], Array[Long]] = {
     val result = srdd.histogram(bucketCount)
-    (result._1.map(scala.Double.box(_)), result._2)
+    (result._1, result._2)
   }
 
   /**