fixes the style comments.

sql/core/src/main/scala/org/apache/spark/sql/Dataset.scala

@@ -451,16 +451,15 @@ class Dataset[T] private[sql](
       c5: TypedColumn[T, U5]): Dataset[(U1, U2, U3, U4, U5)] =
     selectUntyped(c1, c2, c3, c4, c5).asInstanceOf[Dataset[(U1, U2, U3, U4, U5)]]
 
-
   /**
-   * Returns a new [[Dataset]] by sampling a fraction of rows.
+   * Returns a new [[Dataset]] by sampling a fraction of records.
    * @since 1.6.0
    */
   def sample(withReplacement: Boolean, fraction: Double, seed: Long) : Dataset[T] =
     withPlan(Sample(0.0, fraction, withReplacement, seed, _))
 
   /**
-   * Returns a new [[Dataset]] by sampling a fraction of rows, using a random seed.
+   * Returns a new [[Dataset]] by sampling a fraction of records, using a random seed.
    * @since 1.6.0
    */
   def sample(withReplacement: Boolean, fraction: Double) : Dataset[T] = {
@@ -560,7 +559,7 @@ class Dataset[T] private[sql](
 
   /**
    * Using inner equi-join to join this [[Dataset]] returning a [[Tuple2]] for each pair
-   * where `condition` evaluates to true
+   * where `condition` evaluates to true.
    *
    * @param other Right side of the join.
    * @param condition Join expression.

sql/core/src/test/scala/org/apache/spark/sql/DatasetSuite.scala

@@ -192,15 +192,15 @@ class DatasetSuite extends QueryTest with SharedSQLContext {
   test("joinWith, expression condition, outer join") {
     val nullInteger = null.asInstanceOf[Integer]
     val nullString = null.asInstanceOf[String]
-    val ds1 = Seq(ClassNullableData("a", new Integer(1)),
-      ClassNullableData("c", new Integer(3))).toDS()
+    val ds1 = Seq(ClassNullableData("a", 1),
+      ClassNullableData("c", 3)).toDS()
     val ds2 = Seq(("a", new Integer(1)),
       ("b", new Integer(2))).toDS()
 
     checkAnswer(
       ds1.joinWith(ds2, $"_1" === $"a", "outer"),
-      (ClassNullableData("a", new Integer(1)), ("a", new Integer(1))),
-      (ClassNullableData("c", new Integer(3)), (nullString, nullInteger)),
+      (ClassNullableData("a", 1), ("a", new Integer(1))),
+      (ClassNullableData("c", 3), (nullString, nullInteger)),
       (ClassNullableData(nullString, nullInteger), ("b", new Integer(2))))
   }
 
@@ -377,15 +377,15 @@ class DatasetSuite extends QueryTest with SharedSQLContext {
     val data = sparkContext.parallelize(1 to n, 2).toDS()
     checkAnswer(
       data.sample(withReplacement = true, 0.05, seed = 13),
-      Seq(5, 10, 52, 73): _*)
+      5, 10, 52, 73)
   }
 
   test("sample without replacement") {
     val n = 100
     val data = sparkContext.parallelize(1 to n, 2).toDS()
     checkAnswer(
       data.sample(withReplacement = false, 0.05, seed = 13),
-      Seq(3, 17, 27, 58, 62): _*)
+      3, 17, 27, 58, 62)
   }
 
   test("SPARK-11436: we should rebind right encoder when join 2 datasets") {