Addressed PR comments

Author: tdas

core/src/main/scala/org/apache/spark/util/ThreadUtils.scala

@@ -89,7 +89,7 @@ private[spark] object ThreadUtils {
   }
 
   /**
-   * Run a piece of code in a new thread, and the get result. Exception in the new thread is
+   * Run a piece of code in a new thread and return the result. Exception in the new thread is
    * thrown in the caller thread with an adjusted stack trace that removes references to this
    * method for clarity. The exception stack traces will be like the following
    *

core/src/test/scala/org/apache/spark/util/ThreadUtilsSuite.scala

@@ -22,6 +22,7 @@ import java.util.concurrent.{CountDownLatch, TimeUnit}
 
 import scala.concurrent.duration._
 import scala.concurrent.{Await, Future}
+import scala.util.Random
 
 import org.apache.spark.SparkFunSuite
 
@@ -74,10 +75,11 @@ class ThreadUtilsSuite extends SparkFunSuite {
     assert(
       runInNewThread("thread-name", isDaemon = false) { Thread.currentThread().isDaemon } === false
     )
+    val uniqueExceptionMessage = "test" + Random.nextInt()
     val exception = intercept[IllegalArgumentException] {
-      runInNewThread("thread-name") { throw new IllegalArgumentException("test") }
+      runInNewThread("thread-name") { throw new IllegalArgumentException(uniqueExceptionMessage) }
     }
-    assert(exception.asInstanceOf[IllegalArgumentException].getMessage.contains("test"))
+    assert(exception.asInstanceOf[IllegalArgumentException].getMessage === uniqueExceptionMessage)
     assert(exception.getStackTrace.mkString("\n").contains(
       "... run in separate thread using org.apache.spark.util.ThreadUtils ...") === true,
       "stack trace does not contain expected place holder"

streaming/src/test/scala/org/apache/spark/streaming/StreamingContextSuite.scala

@@ -180,7 +180,7 @@ class StreamingContextSuite extends SparkFunSuite with BeforeAndAfter with Timeo
     assert(ssc.scheduler.isStarted === false)
   }
 
-  test("start should set job group correctly") {
+  test("start should set job group and description of streaming jobs correctly") {
     ssc = new StreamingContext(conf, batchDuration)
     ssc.sc.setJobGroup("non-streaming", "non-streaming", true)
     val sc = ssc.sc
@@ -198,7 +198,7 @@ class StreamingContextSuite extends SparkFunSuite with BeforeAndAfter with Timeo
     }
     ssc.start()
 
-    eventually(timeout(5 seconds), interval(10 milliseconds)) {
+    eventually(timeout(10 seconds), interval(10 milliseconds)) {
       assert(allFound === true)
     }