SPARK-1446: Spark examples should not do a System.exit

Spark examples should exit nice using SparkContext.stop() method, rather than System.exit
System.exit can cause issues like in SPARK-1407

Author: Sandeep <sandeep@techaddict.me>

Closes #370 from techaddict/1446 and squashes the following commits:

e9234cf [Sandeep] SPARK-1446: Spark examples should not do a System.exit Spark examples should exit nice using SparkContext.stop() method, rather than System.exit System.exit can cause issues like in SPARK-1407

35 files changed, 60 insertions, 67 deletions

diff --git a/examples/src/main/java/org/apache/spark/examples/JavaHdfsLR.java b/examples/src/main/java/org/apache/spark/examples/JavaHdfsLR.java
index 6b49244ba4..bd96274021 100644
--- a/examples/src/main/java/org/apache/spark/examples/JavaHdfsLR.java
+++ b/examples/src/main/java/org/apache/spark/examples/JavaHdfsLR.java
@@ -138,6 +138,6 @@ public final class JavaHdfsLR {
 
     System.out.print("Final w: ");
     printWeights(w);
-    System.exit(0);
+    sc.stop();
   }
 }
diff --git a/examples/src/main/java/org/apache/spark/examples/JavaLogQuery.java b/examples/src/main/java/org/apache/spark/examples/JavaLogQuery.java
index 617e4a6d04..2a4278d3c3 100644
--- a/examples/src/main/java/org/apache/spark/examples/JavaLogQuery.java
+++ b/examples/src/main/java/org/apache/spark/examples/JavaLogQuery.java
@@ -126,6 +126,6 @@ public final class JavaLogQuery {
     for (Tuple2<?,?> t : output) {
       System.out.println(t._1() + "\t" + t._2());
     }
-    System.exit(0);
+    jsc.stop();
   }
 }
diff --git a/examples/src/main/java/org/apache/spark/examples/JavaPageRank.java b/examples/src/main/java/org/apache/spark/examples/JavaPageRank.java
index 8513ba07e7..e31f676f5f 100644
--- a/examples/src/main/java/org/apache/spark/examples/JavaPageRank.java
+++ b/examples/src/main/java/org/apache/spark/examples/JavaPageRank.java
@@ -117,6 +117,6 @@ public final class JavaPageRank {
         System.out.println(tuple._1() + " has rank: " + tuple._2() + ".");
     }
 
-    System.exit(0);
+    ctx.stop();
   }
 }
diff --git a/examples/src/main/java/org/apache/spark/examples/JavaTC.java b/examples/src/main/java/org/apache/spark/examples/JavaTC.java
index 6cfe25c80e..1d776940f0 100644
--- a/examples/src/main/java/org/apache/spark/examples/JavaTC.java
+++ b/examples/src/main/java/org/apache/spark/examples/JavaTC.java
@@ -96,6 +96,6 @@ public final class JavaTC {
     } while (nextCount != oldCount);
 
     System.out.println("TC has " + tc.count() + " edges.");
-    System.exit(0);
+    sc.stop();
   }
 }
diff --git a/examples/src/main/java/org/apache/spark/examples/JavaWordCount.java b/examples/src/main/java/org/apache/spark/examples/JavaWordCount.java
index 3ae1d8f7ca..87c1b80981 100644
--- a/examples/src/main/java/org/apache/spark/examples/JavaWordCount.java
+++ b/examples/src/main/java/org/apache/spark/examples/JavaWordCount.java
@@ -48,14 +48,14 @@ public final class JavaWordCount {
         return Arrays.asList(SPACE.split(s));
       }
     });
-    
+
     JavaPairRDD<String, Integer> ones = words.mapToPair(new PairFunction<String, String, Integer>() {
       @Override
       public Tuple2<String, Integer> call(String s) {
         return new Tuple2<String, Integer>(s, 1);
       }
     });
-    
+
     JavaPairRDD<String, Integer> counts = ones.reduceByKey(new Function2<Integer, Integer, Integer>() {
       @Override
       public Integer call(Integer i1, Integer i2) {
@@ -67,6 +67,6 @@ public final class JavaWordCount {
     for (Tuple2<?,?> tuple : output) {
       System.out.println(tuple._1() + ": " + tuple._2());
     }
-    System.exit(0);
+    ctx.stop();
   }
 }
diff --git a/examples/src/main/java/org/apache/spark/mllib/examples/JavaALS.java b/examples/src/main/java/org/apache/spark/mllib/examples/JavaALS.java
index 64a3a04fb7..c516199d61 100644
--- a/examples/src/main/java/org/apache/spark/mllib/examples/JavaALS.java
+++ b/examples/src/main/java/org/apache/spark/mllib/examples/JavaALS.java
@@ -85,6 +85,6 @@ public final class JavaALS {
         outputDir + "/productFeatures");
     System.out.println("Final user/product features written to " + outputDir);
 
-    System.exit(0);
+    sc.stop();
   }
 }
diff --git a/examples/src/main/java/org/apache/spark/mllib/examples/JavaKMeans.java b/examples/src/main/java/org/apache/spark/mllib/examples/JavaKMeans.java
index 7b0ec36424..7461609ab9 100644
--- a/examples/src/main/java/org/apache/spark/mllib/examples/JavaKMeans.java
+++ b/examples/src/main/java/org/apache/spark/mllib/examples/JavaKMeans.java
@@ -79,6 +79,6 @@ public final class JavaKMeans {
     double cost = model.computeCost(points.rdd());
     System.out.println("Cost: " + cost);
 
-    System.exit(0);
+    sc.stop();
   }
 }
diff --git a/examples/src/main/java/org/apache/spark/mllib/examples/JavaLR.java b/examples/src/main/java/org/apache/spark/mllib/examples/JavaLR.java
index cd8879ff88..e3ab87cc72 100644
--- a/examples/src/main/java/org/apache/spark/mllib/examples/JavaLR.java
+++ b/examples/src/main/java/org/apache/spark/mllib/examples/JavaLR.java
@@ -77,6 +77,6 @@ public final class JavaLR {
 
     System.out.print("Final w: " + model.weights());
 
-    System.exit(0);
+    sc.stop();
   }
 }
diff --git a/examples/src/main/scala/org/apache/spark/examples/BroadcastTest.scala b/examples/src/main/scala/org/apache/spark/examples/BroadcastTest.scala
index 4d2f45df85..c8c916bb45 100644
--- a/examples/src/main/scala/org/apache/spark/examples/BroadcastTest.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/BroadcastTest.scala
@@ -56,6 +56,6 @@ object BroadcastTest {
       println("Iteration %d took %.0f milliseconds".format(i, (System.nanoTime - startTime) / 1E6))
     }
 
-    System.exit(0)
+    sc.stop()
   }
 }
diff --git a/examples/src/main/scala/org/apache/spark/examples/CassandraCQLTest.scala b/examples/src/main/scala/org/apache/spark/examples/CassandraCQLTest.scala
index ee283ce6ab..1f8d7cb599 100644
--- a/examples/src/main/scala/org/apache/spark/examples/CassandraCQLTest.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/CassandraCQLTest.scala
@@ -58,7 +58,7 @@ import org.apache.spark.SparkContext._
     prod_id,
     quantity) VALUES ('charlie', 1385983649000, 'iphone', 2);
 */
- 
+
 /**
  * This example demonstrates how to read and write to cassandra column family created using CQL3
  * using Spark.
diff --git a/examples/src/main/scala/org/apache/spark/examples/ExceptionHandlingTest.scala b/examples/src/main/scala/org/apache/spark/examples/ExceptionHandlingTest.scala
index fdb976dfc6..be7d39549a 100644
--- a/examples/src/main/scala/org/apache/spark/examples/ExceptionHandlingTest.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/ExceptionHandlingTest.scala
@@ -34,6 +34,6 @@ object ExceptionHandlingTest {
       }
     }
 
-    System.exit(0)
+    sc.stop()
   }
 }
diff --git a/examples/src/main/scala/org/apache/spark/examples/GroupByTest.scala b/examples/src/main/scala/org/apache/spark/examples/GroupByTest.scala
index 36534e5935..29114c6dab 100644
--- a/examples/src/main/scala/org/apache/spark/examples/GroupByTest.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/GroupByTest.scala
@@ -28,7 +28,7 @@ object GroupByTest {
         "Usage: GroupByTest <master> [numMappers] [numKVPairs] [KeySize] [numReducers]")
       System.exit(1)
     }
-    
+
     var numMappers = if (args.length > 1) args(1).toInt else 2
     var numKVPairs = if (args.length > 2) args(2).toInt else 1000
     var valSize = if (args.length > 3) args(3).toInt else 1000
@@ -52,7 +52,6 @@ object GroupByTest {
 
     println(pairs1.groupByKey(numReducers).count)
 
-    System.exit(0)
+    sc.stop()
   }
 }
-
diff --git a/examples/src/main/scala/org/apache/spark/examples/HBaseTest.scala b/examples/src/main/scala/org/apache/spark/examples/HBaseTest.scala
index 65d67356be..700121d16d 100644
--- a/examples/src/main/scala/org/apache/spark/examples/HBaseTest.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/HBaseTest.scala
@@ -30,7 +30,7 @@ object HBaseTest {
 
     val conf = HBaseConfiguration.create()
 
-    // Other options for configuring scan behavior are available. More information available at 
+    // Other options for configuring scan behavior are available. More information available at
     // http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/mapreduce/TableInputFormat.html
     conf.set(TableInputFormat.INPUT_TABLE, args(1))
 
@@ -41,12 +41,12 @@ object HBaseTest {
       admin.createTable(tableDesc)
     }
 
-    val hBaseRDD = sc.newAPIHadoopRDD(conf, classOf[TableInputFormat], 
+    val hBaseRDD = sc.newAPIHadoopRDD(conf, classOf[TableInputFormat],
       classOf[org.apache.hadoop.hbase.io.ImmutableBytesWritable],
       classOf[org.apache.hadoop.hbase.client.Result])
 
     hBaseRDD.count()
 
-    System.exit(0)
+    sc.stop()
   }
 }
diff --git a/examples/src/main/scala/org/apache/spark/examples/HdfsTest.scala b/examples/src/main/scala/org/apache/spark/examples/HdfsTest.scala
index c3597d94a2..dd6d520513 100644
--- a/examples/src/main/scala/org/apache/spark/examples/HdfsTest.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/HdfsTest.scala
@@ -32,6 +32,6 @@ object HdfsTest {
       val end = System.currentTimeMillis()
       println("Iteration " + iter + " took " + (end-start) + " ms")
     }
-    System.exit(0)
+    sc.stop()
   }
 }
diff --git a/examples/src/main/scala/org/apache/spark/examples/LocalALS.scala b/examples/src/main/scala/org/apache/spark/examples/LocalALS.scala
index 0095cb8425..37ad4bd099 100644
--- a/examples/src/main/scala/org/apache/spark/examples/LocalALS.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/LocalALS.scala
@@ -120,7 +120,7 @@ object LocalALS {
       }
     }
     printf("Running with M=%d, U=%d, F=%d, iters=%d\n", M, U, F, ITERATIONS)
-    
+
     val R = generateR()
 
     // Initialize m and u randomly
diff --git a/examples/src/main/scala/org/apache/spark/examples/MultiBroadcastTest.scala b/examples/src/main/scala/org/apache/spark/examples/MultiBroadcastTest.scala
index 4aef04fc06..97321ab8f4 100644
--- a/examples/src/main/scala/org/apache/spark/examples/MultiBroadcastTest.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/MultiBroadcastTest.scala
@@ -51,6 +51,6 @@ object MultiBroadcastTest {
     // Collect the small RDD so we can print the observed sizes locally.
     observedSizes.collect().foreach(i => println(i))
 
-    System.exit(0)
+    sc.stop()
   }
 }
diff --git a/examples/src/main/scala/org/apache/spark/examples/SimpleSkewedGroupByTest.scala b/examples/src/main/scala/org/apache/spark/examples/SimpleSkewedGroupByTest.scala
index 1fdb324b89..d05eedd31c 100644
--- a/examples/src/main/scala/org/apache/spark/examples/SimpleSkewedGroupByTest.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/SimpleSkewedGroupByTest.scala
@@ -27,7 +27,7 @@ object SimpleSkewedGroupByTest {
       System.err.println("Usage: SimpleSkewedGroupByTest <master> " +
         "[numMappers] [numKVPairs] [valSize] [numReducers] [ratio]")
       System.exit(1)
-    }  
+    }
 
     var numMappers = if (args.length > 1) args(1).toInt else 2
     var numKVPairs = if (args.length > 2) args(2).toInt else 1000
@@ -58,14 +58,13 @@ object SimpleSkewedGroupByTest {
     }.cache
     // Enforce that everything has been calculated and in cache
     pairs1.count
-    
+
     println("RESULT: " + pairs1.groupByKey(numReducers).count)
     // Print how many keys each reducer got (for debugging)
     // println("RESULT: " + pairs1.groupByKey(numReducers)
     //                           .map{case (k,v) => (k, v.size)}
     //                           .collectAsMap)
 
-    System.exit(0)
+    sc.stop()
   }
 }
-
diff --git a/examples/src/main/scala/org/apache/spark/examples/SkewedGroupByTest.scala b/examples/src/main/scala/org/apache/spark/examples/SkewedGroupByTest.scala
index 966478fe4a..fd9f043247 100644
--- a/examples/src/main/scala/org/apache/spark/examples/SkewedGroupByTest.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/SkewedGroupByTest.scala
@@ -27,7 +27,7 @@ object SkewedGroupByTest {
       System.err.println(
         "Usage: GroupByTest <master> [numMappers] [numKVPairs] [KeySize] [numReducers]")
       System.exit(1)
-    }  
+    }
 
     var numMappers = if (args.length > 1) args(1).toInt else 2
     var numKVPairs = if (args.length > 2) args(2).toInt else 1000
@@ -53,10 +53,9 @@ object SkewedGroupByTest {
     }.cache()
     // Enforce that everything has been calculated and in cache
     pairs1.count()
-    
+
     println(pairs1.groupByKey(numReducers).count())
 
-    System.exit(0)
+    sc.stop()
   }
 }
-
diff --git a/examples/src/main/scala/org/apache/spark/examples/SparkALS.scala b/examples/src/main/scala/org/apache/spark/examples/SparkALS.scala
index f59ab7e7cc..68f151a2c4 100644
--- a/examples/src/main/scala/org/apache/spark/examples/SparkALS.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/SparkALS.scala
@@ -112,7 +112,7 @@ object SparkALS {
 
     val sc = new SparkContext(host, "SparkALS",
       System.getenv("SPARK_HOME"), SparkContext.jarOfClass(this.getClass))
-    
+
     val R = generateR()
 
     // Initialize m and u randomly
@@ -137,6 +137,6 @@ object SparkALS {
       println()
     }
 
-    System.exit(0)
+    sc.stop()
   }
 }
diff --git a/examples/src/main/scala/org/apache/spark/examples/SparkHdfsLR.scala b/examples/src/main/scala/org/apache/spark/examples/SparkHdfsLR.scala
index 038afbcba8..d8de8745c1 100644
--- a/examples/src/main/scala/org/apache/spark/examples/SparkHdfsLR.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/SparkHdfsLR.scala
@@ -52,7 +52,7 @@ object SparkHdfsLR {
     val inputPath = args(1)
     val conf = SparkHadoopUtil.get.newConfiguration()
     val sc = new SparkContext(args(0), "SparkHdfsLR",
-      System.getenv("SPARK_HOME"), SparkContext.jarOfClass(this.getClass), Map(), 
+      System.getenv("SPARK_HOME"), SparkContext.jarOfClass(this.getClass), Map(),
       InputFormatInfo.computePreferredLocations(
         Seq(new InputFormatInfo(conf, classOf[org.apache.hadoop.mapred.TextInputFormat], inputPath))
       ))
diff --git a/examples/src/main/scala/org/apache/spark/examples/SparkKMeans.scala b/examples/src/main/scala/org/apache/spark/examples/SparkKMeans.scala
index 9fe2465235..1a8b21618e 100644
--- a/examples/src/main/scala/org/apache/spark/examples/SparkKMeans.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/SparkKMeans.scala
@@ -28,16 +28,16 @@ import org.apache.spark.SparkContext._
 object SparkKMeans {
   val R = 1000     // Scaling factor
   val rand = new Random(42)
-    
+
   def parseVector(line: String): Vector = {
     new Vector(line.split(' ').map(_.toDouble))
   }
-  
+
   def closestPoint(p: Vector, centers: Array[Vector]): Int = {
     var index = 0
     var bestIndex = 0
     var closest = Double.PositiveInfinity
-  
+
     for (i <- 0 until centers.length) {
       val tempDist = p.squaredDist(centers(i))
       if (tempDist < closest) {
@@ -45,7 +45,7 @@ object SparkKMeans {
         bestIndex = i
       }
     }
-  
+
     bestIndex
   }
 
@@ -60,22 +60,22 @@ object SparkKMeans {
     val data = lines.map(parseVector _).cache()
     val K = args(2).toInt
     val convergeDist = args(3).toDouble
-  
+
     val kPoints = data.takeSample(withReplacement = false, K, 42).toArray
     var tempDist = 1.0
 
     while(tempDist > convergeDist) {
       val closest = data.map (p => (closestPoint(p, kPoints), (p, 1)))
-      
+
       val pointStats = closest.reduceByKey{case ((x1, y1), (x2, y2)) => (x1 + x2, y1 + y2)}
-      
+
       val newPoints = pointStats.map {pair => (pair._1, pair._2._1 / pair._2._2)}.collectAsMap()
-      
+
       tempDist = 0.0
       for (i <- 0 until K) {
         tempDist += kPoints(i).squaredDist(newPoints(i))
       }
-      
+
       for (newP <- newPoints) {
         kPoints(newP._1) = newP._2
       }
@@ -84,6 +84,6 @@ object SparkKMeans {
 
     println("Final centers:")
     kPoints.foreach(println)
-    System.exit(0)
+    sc.stop()
   }
 }
diff --git a/examples/src/main/scala/org/apache/spark/examples/SparkLR.scala b/examples/src/main/scala/org/apache/spark/examples/SparkLR.scala
index c54a55bdb4..3a2699d4d9 100644
--- a/examples/src/main/scala/org/apache/spark/examples/SparkLR.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/SparkLR.scala
@@ -66,6 +66,6 @@ object SparkLR {
     }
 
     println("Final w: " + w)
-    System.exit(0)
+    sc.stop()
   }
 }
diff --git a/examples/src/main/scala/org/apache/spark/examples/SparkPageRank.scala b/examples/src/main/scala/org/apache/spark/examples/SparkPageRank.scala
index d203f4d20e..45b6e10f3e 100644
--- a/examples/src/main/scala/org/apache/spark/examples/SparkPageRank.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/SparkPageRank.scala
@@ -57,7 +57,6 @@ object SparkPageRank {
     val output = ranks.collect()
     output.foreach(tup => println(tup._1 + " has rank: " + tup._2 + "."))
 
-    System.exit(0)
+    ctx.stop()
   }
 }
-
diff --git a/examples/src/main/scala/org/apache/spark/examples/SparkTC.scala b/examples/src/main/scala/org/apache/spark/examples/SparkTC.scala
index 24e8afa26b..eb47cf027c 100644
--- a/examples/src/main/scala/org/apache/spark/examples/SparkTC.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/SparkTC.scala
@@ -70,6 +70,6 @@ object SparkTC {
     } while (nextCount != oldCount)
 
     println("TC has " + tc.count() + " edges.")
-    System.exit(0)
+    spark.stop()
   }
 }
diff --git a/examples/src/main/scala/org/apache/spark/examples/SparkTachyonHdfsLR.scala b/examples/src/main/scala/org/apache/spark/examples/SparkTachyonHdfsLR.scala
index 53b303d658..5698d47464 100644
--- a/examples/src/main/scala/org/apache/spark/examples/SparkTachyonHdfsLR.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/SparkTachyonHdfsLR.scala
@@ -75,6 +75,6 @@ object SparkTachyonHdfsLR {
     }
 
     println("Final w: " + w)
-    System.exit(0)
+    sc.stop()
   }
 }
diff --git a/examples/src/main/scala/org/apache/spark/examples/SparkTachyonPi.scala b/examples/src/main/scala/org/apache/spark/examples/SparkTachyonPi.scala
index ce78f0876e..2b207fd8d3 100644
--- a/examples/src/main/scala/org/apache/spark/examples/SparkTachyonPi.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/SparkTachyonPi.scala
@@ -34,10 +34,10 @@ object SparkTachyonPi {
     }
     val spark = new SparkContext(args(0), "SparkTachyonPi",
       System.getenv("SPARK_HOME"), SparkContext.jarOfClass(this.getClass))
-    
+
     val slices = if (args.length > 1) args(1).toInt else 2
     val n = 100000 * slices
-    
+
     val rdd = spark.parallelize(1 to n, slices)
     rdd.persist(StorageLevel.OFF_HEAP)
     val count = rdd.map { i =>
@@ -46,7 +46,7 @@ object SparkTachyonPi {
       if (x * x + y * y < 1) 1 else 0
     }.reduce(_ + _)
     println("Pi is roughly " + 4.0 * count / n)
-    
+
     spark.stop()
   }
 }
diff --git a/examples/src/main/scala/org/apache/spark/examples/bagel/WikipediaPageRankStandalone.scala b/examples/src/main/scala/org/apache/spark/examples/bagel/WikipediaPageRankStandalone.scala
index 7aac6a1359..dee3cb6c0a 100644
--- a/examples/src/main/scala/org/apache/spark/examples/bagel/WikipediaPageRankStandalone.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/bagel/WikipediaPageRankStandalone.scala
@@ -79,7 +79,7 @@ object WikipediaPageRankStandalone {
     val time = (System.currentTimeMillis - startTime) / 1000.0
     println("Completed %d iterations in %f seconds: %f seconds per iteration"
       .format(numIterations, time, time / numIterations))
-    System.exit(0)
+    sc.stop()
   }
 
   def parseArticle(line: String): (String, Array[String]) = {
diff --git a/examples/src/main/scala/org/apache/spark/examples/mllib/TallSkinnyPCA.scala b/examples/src/main/scala/org/apache/spark/examples/mllib/TallSkinnyPCA.scala
index a177435e60..61b9655cd3 100644
--- a/examples/src/main/scala/org/apache/spark/examples/mllib/TallSkinnyPCA.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/mllib/TallSkinnyPCA.scala
@@ -16,7 +16,7 @@
  */
 
 package org.apache.spark.examples.mllib
-      
+
 import org.apache.spark.{SparkConf, SparkContext}
 import org.apache.spark.mllib.linalg.distributed.RowMatrix
 import org.apache.spark.mllib.linalg.Vectors
diff --git a/examples/src/main/scala/org/apache/spark/examples/mllib/TallSkinnySVD.scala b/examples/src/main/scala/org/apache/spark/examples/mllib/TallSkinnySVD.scala
index 49d09692c8..9aeebf58ea 100644
--- a/examples/src/main/scala/org/apache/spark/examples/mllib/TallSkinnySVD.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/mllib/TallSkinnySVD.scala
@@ -16,7 +16,7 @@
  */
 
 package org.apache.spark.examples.mllib
-      
+
 import org.apache.spark.{SparkConf, SparkContext}
 import org.apache.spark.mllib.linalg.distributed.RowMatrix
 import org.apache.spark.mllib.linalg.Vectors
diff --git a/examples/src/main/scala/org/apache/spark/streaming/examples/HdfsWordCount.scala b/examples/src/main/scala/org/apache/spark/streaming/examples/HdfsWordCount.scala
index 954bcc9b6e..1c0ce3111e 100644
--- a/examples/src/main/scala/org/apache/spark/streaming/examples/HdfsWordCount.scala
+++ b/examples/src/main/scala/org/apache/spark/streaming/examples/HdfsWordCount.scala
@@ -53,4 +53,3 @@ object HdfsWordCount {
     ssc.awaitTermination()
   }
 }
-
diff --git a/examples/src/main/scala/org/apache/spark/streaming/examples/KafkaWordCount.scala b/examples/src/main/scala/org/apache/spark/streaming/examples/KafkaWordCount.scala
index 6bccd1d884..cca0be2cbb 100644
--- a/examples/src/main/scala/org/apache/spark/streaming/examples/KafkaWordCount.scala
+++ b/examples/src/main/scala/org/apache/spark/streaming/examples/KafkaWordCount.scala
@@ -61,7 +61,7 @@ object KafkaWordCount {
     val wordCounts = words.map(x => (x, 1L))
       .reduceByKeyAndWindow(add _, subtract _, Minutes(10), Seconds(2), 2)
     wordCounts.print()
-    
+
     ssc.start()
     ssc.awaitTermination()
   }
@@ -83,7 +83,7 @@ object KafkaWordCountProducer {
     val props = new Properties()
     props.put("metadata.broker.list", brokers)
     props.put("serializer.class", "kafka.serializer.StringEncoder")
-    
+
     val config = new ProducerConfig(props)
     val producer = new Producer[String, String](config)
 
@@ -102,4 +102,3 @@ object KafkaWordCountProducer {
   }
 
 }
-
diff --git a/examples/src/main/scala/org/apache/spark/streaming/examples/MQTTWordCount.scala b/examples/src/main/scala/org/apache/spark/streaming/examples/MQTTWordCount.scala
index 0a68ac84c2..656222e0c1 100644
--- a/examples/src/main/scala/org/apache/spark/streaming/examples/MQTTWordCount.scala
+++ b/examples/src/main/scala/org/apache/spark/streaming/examples/MQTTWordCount.scala
@@ -26,7 +26,7 @@ import org.apache.spark.streaming.StreamingContext._
 import org.apache.spark.streaming.mqtt._
 
 /**
- * A simple Mqtt publisher for demonstration purposes, repeatedly publishes 
+ * A simple Mqtt publisher for demonstration purposes, repeatedly publishes
  * Space separated String Message "hello mqtt demo for spark streaming"
  */
 object MQTTPublisher {
diff --git a/examples/src/main/scala/org/apache/spark/streaming/examples/QueueStream.scala b/examples/src/main/scala/org/apache/spark/streaming/examples/QueueStream.scala
index 4d4968ba6a..612ecf7b78 100644
--- a/examples/src/main/scala/org/apache/spark/streaming/examples/QueueStream.scala
+++ b/examples/src/main/scala/org/apache/spark/streaming/examples/QueueStream.scala
@@ -24,7 +24,7 @@ import org.apache.spark.streaming.{Seconds, StreamingContext}
 import org.apache.spark.streaming.StreamingContext._
 
 object QueueStream {
-  
+
   def main(args: Array[String]) {
     if (args.length < 1) {
       System.err.println("Usage: QueueStream <master>")
@@ -37,23 +37,22 @@ object QueueStream {
     val ssc = new StreamingContext(args(0), "QueueStream", Seconds(1),
       System.getenv("SPARK_HOME"), StreamingContext.jarOfClass(this.getClass))
 
-    // Create the queue through which RDDs can be pushed to 
+    // Create the queue through which RDDs can be pushed to
     // a QueueInputDStream
     val rddQueue = new SynchronizedQueue[RDD[Int]]()
-    
+
     // Create the QueueInputDStream and use it do some processing
     val inputStream = ssc.queueStream(rddQueue)
     val mappedStream = inputStream.map(x => (x % 10, 1))
     val reducedStream = mappedStream.reduceByKey(_ + _)
-    reducedStream.print()    
+    reducedStream.print()
     ssc.start()
-    
+
     // Create and push some RDDs into
     for (i <- 1 to 30) {
       rddQueue += ssc.sparkContext.makeRDD(1 to 1000, 10)
       Thread.sleep(1000)
     }
     ssc.stop()
-    System.exit(0)
   }
 }
diff --git a/examples/src/main/scala/org/apache/spark/streaming/examples/StatefulNetworkWordCount.scala b/examples/src/main/scala/org/apache/spark/streaming/examples/StatefulNetworkWordCount.scala
index c2d84a8e08..14f65a2f8d 100644
--- a/examples/src/main/scala/org/apache/spark/streaming/examples/StatefulNetworkWordCount.scala
+++ b/examples/src/main/scala/org/apache/spark/streaming/examples/StatefulNetworkWordCount.scala
@@ -58,7 +58,7 @@ object StatefulNetworkWordCount {
     ssc.checkpoint(".")
 
     // Create a NetworkInputDStream on target ip:port and count the
-    // words in input stream of \n delimited test (eg. generated by 'nc') 
+    // words in input stream of \n delimited test (eg. generated by 'nc')
     val lines = ssc.socketTextStream(args(1), args(2).toInt)
     val words = lines.flatMap(_.split(" "))
     val wordDstream = words.map(x => (x, 1))
diff --git a/examples/src/main/scala/org/apache/spark/streaming/examples/ZeroMQWordCount.scala b/examples/src/main/scala/org/apache/spark/streaming/examples/ZeroMQWordCount.scala
index 35f8f885f8..445d202858 100644
--- a/examples/src/main/scala/org/apache/spark/streaming/examples/ZeroMQWordCount.scala
+++ b/examples/src/main/scala/org/apache/spark/streaming/examples/ZeroMQWordCount.scala
@@ -60,7 +60,7 @@ object SimpleZeroMQPublisher {
  * To work with zeroMQ, some native libraries have to be installed.
  * Install zeroMQ (release 2.1) core libraries. [ZeroMQ Install guide]
  * (http://www.zeromq.org/intro:get-the-software)
- * 
+ *
  * Usage: ZeroMQWordCount <master> <zeroMQurl> <topic>
  * In local mode, <master> should be 'local[n]' with n > 1
  *   <zeroMQurl> and <topic> describe where zeroMq publisher is running.