Small documentation and style fix.

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/Statistics.scala

@@ -31,5 +31,6 @@ package org.apache.spark.sql.catalyst.plans.logical
  *
  * @param sizeInBytes Physical size in bytes. For leaf operators this defaults to 1, otherwise it
  *                    defaults to the product of children's `sizeInBytes`.
+ * @param isBroadcastable If true, output is small enough to be used in a broadcast join.
  */
-private[sql] case class Statistics(sizeInBytes: BigInt, isBroadcastable: Boolean = false)
+case class Statistics(sizeInBytes: BigInt, isBroadcastable: Boolean = false)

sql/core/src/test/scala/org/apache/spark/sql/execution/joins/BroadcastJoinSuite.scala

@@ -19,8 +19,6 @@ package org.apache.spark.sql.execution.joins
 
 import scala.reflect.ClassTag
 
-import org.scalatest.BeforeAndAfterAll
-
 import org.apache.spark.{AccumulatorSuite, SparkConf, SparkContext}
 import org.apache.spark.sql.{Dataset, QueryTest, Row, SparkSession}
 import org.apache.spark.sql.execution.exchange.EnsureRequirements
@@ -68,10 +66,11 @@ class BroadcastJoinSuite extends QueryTest with SQLTestUtils {
     }
   }
 
-  private def testBroadcastJoin[T: ClassTag](joinType: String,
-                                             forceBroadcast: Boolean = false): SparkPlan = {
+  private def testBroadcastJoin[T: ClassTag](
+      joinType: String,
+      forceBroadcast: Boolean = false): SparkPlan = {
     val df1 = spark.createDataFrame(Seq((1, "4"), (2, "2"))).toDF("key", "value")
-    var df2 = spark.createDataFrame(Seq((1, "1"), (2, "2"))).toDF("key", "value")
+    val df2 = spark.createDataFrame(Seq((1, "1"), (2, "2"))).toDF("key", "value")
 
     // Comparison at the end is for broadcast left semi join
     val joinExpression = df1("key") === df2("key") && df1("value") > df2("value")
@@ -80,11 +79,9 @@ class BroadcastJoinSuite extends QueryTest with SQLTestUtils {
     } else {
       df1.join(df2, joinExpression, joinType)
     }
-    val plan =
-      EnsureRequirements(spark.sessionState.conf).apply(df3.queryExecution.sparkPlan)
+    val plan = EnsureRequirements(spark.sessionState.conf).apply(df3.queryExecution.sparkPlan)
     assert(plan.collect { case p: T => p }.size === 1)
-
-    return plan
+    plan
   }
 
   test("unsafe broadcast hash join updates peak execution memory") {