[SPARK-20554][BUILD] Remove usage of scala.language.reflectiveCalls

## What changes were proposed in this pull request?

Remove uses of scala.language.reflectiveCalls that are either unnecessary or probably resulting in more complex code. This turned out to be less significant than I thought, but, still worth a touch-up.

## How was this patch tested?

Existing tests.

Author: Sean Owen <sowen@cloudera.com>

Closes #17949 from srowen/SPARK-20554.

core/src/test/scala/org/apache/spark/storage/DiskBlockManagerSuite.scala

@@ -19,8 +19,6 @@ package org.apache.spark.storage
 
 import java.io.{File, FileWriter}
 
-import scala.language.reflectiveCalls
-
 import org.scalatest.{BeforeAndAfterAll, BeforeAndAfterEach}
 
 import org.apache.spark.{SparkConf, SparkFunSuite}

core/src/test/scala/org/apache/spark/util/random/XORShiftRandomSuite.scala

@@ -17,8 +17,6 @@
 
 package org.apache.spark.util.random
 
-import scala.language.reflectiveCalls
-
 import org.apache.commons.math3.stat.inference.ChiSquareTest
 import org.scalatest.Matchers
 
@@ -27,26 +25,22 @@ import org.apache.spark.util.Utils.times
 
 class XORShiftRandomSuite extends SparkFunSuite with Matchers {
 
-  private def fixture = new {
-    val seed = 1L
-    val xorRand = new XORShiftRandom(seed)
-    val hundMil = 1e8.toInt
-  }
-
   /*
    * This test is based on a chi-squared test for randomness.
    */
   test ("XORShift generates valid random numbers") {
 
-    val f = fixture
+    val xorRand = new XORShiftRandom(1L)
 
     val numBins = 10 // create 10 bins
     val numRows = 5 // create 5 rows
     val bins = Array.ofDim[Long](numRows, numBins)
 
     // populate bins based on modulus of the random number for each row
-    for (r <- 0 to numRows-1) {
+    for (r <- 0 until numRows) {
-      times(f.hundMil) {bins(r)(math.abs(f.xorRand.nextInt) % numBins) += 1}
+      times(100000000) {
+        bins(r)(math.abs(xorRand.nextInt) % numBins) += 1
+      }
     }
 
     /*

examples/src/main/scala/org/apache/spark/examples/ml/DecisionTreeExample.scala

@@ -21,7 +21,6 @@ package org.apache.spark.examples.ml
 import java.util.Locale
 
 import scala.collection.mutable
-import scala.language.reflectiveCalls
 
 import scopt.OptionParser
 

examples/src/main/scala/org/apache/spark/examples/ml/GBTExample.scala

@@ -21,7 +21,6 @@ package org.apache.spark.examples.ml
 import java.util.Locale
 
 import scala.collection.mutable
-import scala.language.reflectiveCalls
 
 import scopt.OptionParser
 

examples/src/main/scala/org/apache/spark/examples/ml/LinearRegressionExample.scala

@@ -18,8 +18,6 @@
 // scalastyle:off println
 package org.apache.spark.examples.ml
 
-import scala.language.reflectiveCalls
-
 import scopt.OptionParser
 
 import org.apache.spark.examples.mllib.AbstractParams

examples/src/main/scala/org/apache/spark/examples/ml/LogisticRegressionExample.scala

@@ -19,7 +19,6 @@
 package org.apache.spark.examples.ml
 
 import scala.collection.mutable
-import scala.language.reflectiveCalls
 
 import scopt.OptionParser
 

examples/src/main/scala/org/apache/spark/examples/ml/RandomForestExample.scala

@@ -21,7 +21,6 @@ package org.apache.spark.examples.ml
 import java.util.Locale
 
 import scala.collection.mutable
-import scala.language.reflectiveCalls
 
 import scopt.OptionParser
 

sql/core/src/test/scala/org/apache/spark/sql/execution/QueryExecutionSuite.scala

@@ -16,39 +16,36 @@
  */
 package org.apache.spark.sql.execution
 
-import java.util.Locale
-
-import scala.language.reflectiveCalls
-
 import org.apache.spark.sql.AnalysisException
 import org.apache.spark.sql.catalyst.plans.logical.{LogicalPlan, OneRowRelation}
 import org.apache.spark.sql.test.SharedSQLContext
 
 class QueryExecutionSuite extends SharedSQLContext {
   test("toString() exception/error handling") {
-    val badRule = new SparkStrategy {
+    spark.experimental.extraStrategies = Seq(
-      var mode: String = ""
+        new SparkStrategy {
-      override def apply(plan: LogicalPlan): Seq[SparkPlan] =
+          override def apply(plan: LogicalPlan): Seq[SparkPlan] = Nil
-        mode.toLowerCase(Locale.ROOT) match {
+        })
-          case "exception" => throw new AnalysisException(mode)
-          case "error" => throw new Error(mode)
-          case _ => Nil
-        }
-    }
-    spark.experimental.extraStrategies = badRule :: Nil
 
     def qe: QueryExecution = new QueryExecution(spark, OneRowRelation)
 
     // Nothing!
-    badRule.mode = ""
     assert(qe.toString.contains("OneRowRelation"))
 
     // Throw an AnalysisException - this should be captured.
-    badRule.mode = "exception"
+    spark.experimental.extraStrategies = Seq(
+      new SparkStrategy {
+        override def apply(plan: LogicalPlan): Seq[SparkPlan] =
+          throw new AnalysisException("exception")
+      })
     assert(qe.toString.contains("org.apache.spark.sql.AnalysisException"))
 
     // Throw an Error - this should not be captured.
-    badRule.mode = "error"
+    spark.experimental.extraStrategies = Seq(
+      new SparkStrategy {
+        override def apply(plan: LogicalPlan): Seq[SparkPlan] =
+          throw new Error("error")
+      })
     val error = intercept[Error](qe.toString)
     assert(error.getMessage.contains("error"))
   }

sql/hive/src/main/scala/org/apache/spark/sql/hive/client/HiveClientImpl.scala

@@ -22,7 +22,6 @@ import java.util.Locale
 
 import scala.collection.JavaConverters._
 import scala.collection.mutable.ArrayBuffer
-import scala.language.reflectiveCalls
 
 import org.apache.hadoop.conf.Configuration
 import org.apache.hadoop.fs.Path

sql/hive/src/main/scala/org/apache/spark/sql/hive/client/IsolatedClientLoader.scala

@@ -22,7 +22,6 @@ import java.lang.reflect.InvocationTargetException
 import java.net.{URL, URLClassLoader}
 import java.util
 
-import scala.language.reflectiveCalls
 import scala.util.Try
 
 import org.apache.commons.io.{FileUtils, IOUtils}

streaming/src/test/scala/org/apache/spark/streaming/receiver/BlockGeneratorSuite.scala

@@ -21,7 +21,6 @@ import java.util.concurrent.ConcurrentLinkedQueue
 
 import scala.collection.JavaConverters._
 import scala.collection.mutable
-import scala.language.reflectiveCalls
 
 import org.scalatest.BeforeAndAfter
 import org.scalatest.Matchers._
@@ -202,21 +201,17 @@ class BlockGeneratorSuite extends SparkFunSuite with BeforeAndAfter {
 
   test("block push errors are reported") {
     val listener = new TestBlockGeneratorListener {
-      @volatile var errorReported = false
       override def onPushBlock(
           blockId: StreamBlockId, arrayBuffer: mutable.ArrayBuffer[_]): Unit = {
         throw new SparkException("test")
       }
-      override def onError(message: String, throwable: Throwable): Unit = {
-        errorReported = true
-      }
     }
     blockGenerator = new BlockGenerator(listener, 0, conf)
     blockGenerator.start()
-    assert(listener.errorReported === false)
+    assert(listener.onErrorCalled === false)
     blockGenerator.addData(1)
     eventually(timeout(1 second), interval(10 milliseconds)) {
-      assert(listener.errorReported === true)
+      assert(listener.onErrorCalled === true)
     }
     blockGenerator.stop()
   }
@@ -243,12 +238,15 @@ class BlockGeneratorSuite extends SparkFunSuite with BeforeAndAfter {
     @volatile var onGenerateBlockCalled = false
     @volatile var onAddDataCalled = false
     @volatile var onPushBlockCalled = false
+    @volatile var onErrorCalled = false
 
     override def onPushBlock(blockId: StreamBlockId, arrayBuffer: mutable.ArrayBuffer[_]): Unit = {
       pushedData.addAll(arrayBuffer.asJava)
       onPushBlockCalled = true
     }
-    override def onError(message: String, throwable: Throwable): Unit = {}
+    override def onError(message: String, throwable: Throwable): Unit = {
+      onErrorCalled = true
+    }
     override def onGenerateBlock(blockId: StreamBlockId): Unit = {
       onGenerateBlockCalled = true
     }