128 files changed, 303 insertions, 284 deletions

diff --git a/core/src/main/scala/org/apache/spark/Accumulators.scala b/core/src/main/scala/org/apache/spark/Accumulators.scala
index 5177ee58fa..6e922a612a 100644
--- a/core/src/main/scala/org/apache/spark/Accumulators.scala
+++ b/core/src/main/scala/org/apache/spark/Accumulators.scala
@@ -21,6 +21,7 @@ import java.io._
 
 import scala.collection.mutable.Map
 import scala.collection.generic.Growable
+import org.apache.spark.serializer.JavaSerializer
 
 /**
  * A datatype that can be accumulated, i.e. has an commutative and associative "add" operation,
diff --git a/core/src/main/scala/org/apache/spark/CacheManager.scala b/core/src/main/scala/org/apache/spark/CacheManager.scala
index 42e465b9d8..e299a106ee 100644
--- a/core/src/main/scala/org/apache/spark/CacheManager.scala
+++ b/core/src/main/scala/org/apache/spark/CacheManager.scala
@@ -19,6 +19,7 @@ package org.apache.spark
 
 import scala.collection.mutable.{ArrayBuffer, HashSet}
 import org.apache.spark.storage.{BlockManager, StorageLevel}
+import org.apache.spark.rdd.RDD
 
 
 /** Spark class responsible for passing RDDs split contents to the BlockManager and making
diff --git a/core/src/main/scala/org/apache/spark/Dependency.scala b/core/src/main/scala/org/apache/spark/Dependency.scala
index cc3c2474a6..cc30105940 100644
--- a/core/src/main/scala/org/apache/spark/Dependency.scala
+++ b/core/src/main/scala/org/apache/spark/Dependency.scala
@@ -17,6 +17,8 @@
 
 package org.apache.spark
 
+import org.apache.spark.rdd.RDD
+
 /**
  * Base class for dependencies.
  */
diff --git a/core/src/main/scala/org/apache/spark/HttpFileServer.scala b/core/src/main/scala/org/apache/spark/HttpFileServer.scala
index 9b3a896648..ad1ee20045 100644
--- a/core/src/main/scala/org/apache/spark/HttpFileServer.scala
+++ b/core/src/main/scala/org/apache/spark/HttpFileServer.scala
@@ -19,6 +19,7 @@ package org.apache.spark
 
 import java.io.{File}
 import com.google.common.io.Files
+import org.apache.spark.util.Utils
 
 private[spark] class HttpFileServer extends Logging {
   
diff --git a/core/src/main/scala/org/apache/spark/HttpServer.scala b/core/src/main/scala/org/apache/spark/HttpServer.scala
index db36c7c9dd..cdfc9dd54e 100644
--- a/core/src/main/scala/org/apache/spark/HttpServer.scala
+++ b/core/src/main/scala/org/apache/spark/HttpServer.scala
@@ -26,6 +26,7 @@ import org.eclipse.jetty.server.handler.DefaultHandler
 import org.eclipse.jetty.server.handler.HandlerList
 import org.eclipse.jetty.server.handler.ResourceHandler
 import org.eclipse.jetty.util.thread.QueuedThreadPool
+import org.apache.spark.util.Utils
 
 /**
  * Exception type thrown by HttpServer when it is in the wrong state for an operation.
diff --git a/core/src/main/scala/org/apache/spark/MapOutputTracker.scala b/core/src/main/scala/org/apache/spark/MapOutputTracker.scala
index 0f422d910a..ae7cf2a893 100644
--- a/core/src/main/scala/org/apache/spark/MapOutputTracker.scala
+++ b/core/src/main/scala/org/apache/spark/MapOutputTracker.scala
@@ -32,7 +32,7 @@ import akka.util.Duration
 
 import org.apache.spark.scheduler.MapStatus
 import org.apache.spark.storage.BlockManagerId
-import org.apache.spark.util.{MetadataCleaner, TimeStampedHashMap}
+import org.apache.spark.util.{Utils, MetadataCleaner, TimeStampedHashMap}
 
 
 private[spark] sealed trait MapOutputTrackerMessage
diff --git a/core/src/main/scala/org/apache/spark/Partitioner.scala b/core/src/main/scala/org/apache/spark/Partitioner.scala
index 4dce2607b0..0e2c987a59 100644
--- a/core/src/main/scala/org/apache/spark/Partitioner.scala
+++ b/core/src/main/scala/org/apache/spark/Partitioner.scala
@@ -17,6 +17,9 @@
 
 package org.apache.spark
 
+import org.apache.spark.util.Utils
+import org.apache.spark.rdd.RDD
+
 /**
  * An object that defines how the elements in a key-value pair RDD are partitioned by key.
  * Maps each key to a partition ID, from 0 to `numPartitions - 1`.
diff --git a/core/src/main/scala/org/apache/spark/SparkContext.scala b/core/src/main/scala/org/apache/spark/SparkContext.scala
index 1207b242bc..faf0c2362a 100644
--- a/core/src/main/scala/org/apache/spark/SparkContext.scala
+++ b/core/src/main/scala/org/apache/spark/SparkContext.scala
@@ -54,17 +54,15 @@ import org.apache.mesos.MesosNativeLibrary
 
 import org.apache.spark.deploy.LocalSparkCluster
 import org.apache.spark.partial.{ApproximateEvaluator, PartialResult}
-import org.apache.spark.rdd.{CheckpointRDD, HadoopRDD, NewHadoopRDD, UnionRDD, ParallelCollectionRDD,
-  OrderedRDDFunctions}
+import org.apache.spark.rdd._
 import org.apache.spark.scheduler._
 import org.apache.spark.scheduler.cluster.{StandaloneSchedulerBackend, SparkDeploySchedulerBackend,
   ClusterScheduler, Schedulable, SchedulingMode}
 import org.apache.spark.scheduler.local.LocalScheduler
 import org.apache.spark.scheduler.mesos.{CoarseMesosSchedulerBackend, MesosSchedulerBackend}
-import org.apache.spark.storage.{StorageStatus, StorageUtils, RDDInfo, BlockManagerSource}
+import org.apache.spark.storage.{StorageUtils, BlockManagerSource}
 import org.apache.spark.ui.SparkUI
-import org.apache.spark.util.{MetadataCleaner, TimeStampedHashMap}
-import scala.Some
+import org.apache.spark.util.{ClosureCleaner, Utils, MetadataCleaner, TimeStampedHashMap}
 import org.apache.spark.scheduler.StageInfo
 import org.apache.spark.storage.RDDInfo
 import org.apache.spark.storage.StorageStatus
diff --git a/core/src/main/scala/org/apache/spark/SparkEnv.scala b/core/src/main/scala/org/apache/spark/SparkEnv.scala
index 6e6fe5df6b..478e5a0aaf 100644
--- a/core/src/main/scala/org/apache/spark/SparkEnv.scala
+++ b/core/src/main/scala/org/apache/spark/SparkEnv.scala
@@ -29,7 +29,7 @@ import org.apache.spark.deploy.SparkHadoopUtil
 import org.apache.spark.storage.{BlockManagerMasterActor, BlockManager, BlockManagerMaster}
 import org.apache.spark.network.ConnectionManager
 import org.apache.spark.serializer.{Serializer, SerializerManager}
-import org.apache.spark.util.AkkaUtils
+import org.apache.spark.util.{Utils, AkkaUtils}
 import org.apache.spark.api.python.PythonWorkerFactory
 
 
@@ -155,10 +155,10 @@ object SparkEnv extends Logging {
     val serializerManager = new SerializerManager
 
     val serializer = serializerManager.setDefault(
-      System.getProperty("spark.serializer", "org.apache.spark.JavaSerializer"))
+      System.getProperty("spark.serializer", "org.apache.spark.serializer.JavaSerializer"))
 
     val closureSerializer = serializerManager.get(
-      System.getProperty("spark.closure.serializer", "org.apache.spark.JavaSerializer"))
+      System.getProperty("spark.closure.serializer", "org.apache.spark.serializer.JavaSerializer"))
 
     def registerOrLookup(name: String, newActor: => Actor): ActorRef = {
       if (isDriver) {
diff --git a/core/src/main/scala/org/apache/spark/api/java/JavaDoubleRDD.scala b/core/src/main/scala/org/apache/spark/api/java/JavaDoubleRDD.scala
index cb25ff728e..5fd1fab580 100644
--- a/core/src/main/scala/org/apache/spark/api/java/JavaDoubleRDD.scala
+++ b/core/src/main/scala/org/apache/spark/api/java/JavaDoubleRDD.scala
@@ -17,7 +17,7 @@
 
 package org.apache.spark.api.java
 
-import org.apache.spark.RDD
+import org.apache.spark.rdd.RDD
 import org.apache.spark.SparkContext.doubleRDDToDoubleRDDFunctions
 import org.apache.spark.api.java.function.{Function => JFunction}
 import org.apache.spark.util.StatCounter
diff --git a/core/src/main/scala/org/apache/spark/api/java/JavaPairRDD.scala b/core/src/main/scala/org/apache/spark/api/java/JavaPairRDD.scala
index 09da35aee6..a6518abf45 100644
--- a/core/src/main/scala/org/apache/spark/api/java/JavaPairRDD.scala
+++ b/core/src/main/scala/org/apache/spark/api/java/JavaPairRDD.scala
@@ -33,12 +33,12 @@ import org.apache.hadoop.conf.Configuration
 import org.apache.spark.HashPartitioner
 import org.apache.spark.Partitioner
 import org.apache.spark.Partitioner._
-import org.apache.spark.RDD
 import org.apache.spark.SparkContext.rddToPairRDDFunctions
 import org.apache.spark.api.java.function.{Function2 => JFunction2}
 import org.apache.spark.api.java.function.{Function => JFunction}
 import org.apache.spark.partial.BoundedDouble
 import org.apache.spark.partial.PartialResult
+import org.apache.spark.rdd.RDD
 import org.apache.spark.rdd.OrderedRDDFunctions
 import org.apache.spark.storage.StorageLevel
 
diff --git a/core/src/main/scala/org/apache/spark/api/java/JavaRDD.scala b/core/src/main/scala/org/apache/spark/api/java/JavaRDD.scala
index 68cfcf5999..eec58abdd6 100644
--- a/core/src/main/scala/org/apache/spark/api/java/JavaRDD.scala
+++ b/core/src/main/scala/org/apache/spark/api/java/JavaRDD.scala
@@ -18,6 +18,7 @@
 package org.apache.spark.api.java
 
 import org.apache.spark._
+import org.apache.spark.rdd.RDD
 import org.apache.spark.api.java.function.{Function => JFunction}
 import org.apache.spark.storage.StorageLevel
 
diff --git a/core/src/main/scala/org/apache/spark/api/java/JavaRDDLike.scala b/core/src/main/scala/org/apache/spark/api/java/JavaRDDLike.scala
index 1ad8514980..7e6e691f11 100644
--- a/core/src/main/scala/org/apache/spark/api/java/JavaRDDLike.scala
+++ b/core/src/main/scala/org/apache/spark/api/java/JavaRDDLike.scala
@@ -21,13 +21,15 @@ import java.util.{List => JList, Comparator}
 import scala.Tuple2
 import scala.collection.JavaConversions._
 
+import com.google.common.base.Optional
 import org.apache.hadoop.io.compress.CompressionCodec
-import org.apache.spark.{SparkContext, Partition, RDD, TaskContext}
+
+import org.apache.spark.{SparkContext, Partition, TaskContext}
+import org.apache.spark.rdd.RDD
 import org.apache.spark.api.java.JavaPairRDD._
 import org.apache.spark.api.java.function.{Function2 => JFunction2, Function => JFunction, _}
 import org.apache.spark.partial.{PartialResult, BoundedDouble}
 import org.apache.spark.storage.StorageLevel
-import com.google.common.base.Optional
 
 
 trait JavaRDDLike[T, This <: JavaRDDLike[T, This]] extends Serializable {
diff --git a/core/src/main/scala/org/apache/spark/api/java/JavaSparkContext.scala b/core/src/main/scala/org/apache/spark/api/java/JavaSparkContext.scala
index 618a7b3bf7..8869e072bf 100644
--- a/core/src/main/scala/org/apache/spark/api/java/JavaSparkContext.scala
+++ b/core/src/main/scala/org/apache/spark/api/java/JavaSparkContext.scala
@@ -26,13 +26,13 @@ import org.apache.hadoop.conf.Configuration
 import org.apache.hadoop.mapred.InputFormat
 import org.apache.hadoop.mapred.JobConf
 import org.apache.hadoop.mapreduce.{InputFormat => NewInputFormat}
+import com.google.common.base.Optional
 
-import org.apache.spark.{Accumulable, AccumulableParam, Accumulator, AccumulatorParam, RDD, SparkContext}
+import org.apache.spark.{Accumulable, AccumulableParam, Accumulator, AccumulatorParam, SparkContext}
 import org.apache.spark.SparkContext.IntAccumulatorParam
 import org.apache.spark.SparkContext.DoubleAccumulatorParam
 import org.apache.spark.broadcast.Broadcast
-
-import com.google.common.base.Optional
+import org.apache.spark.rdd.RDD
 
 /**
  * A Java-friendly version of [[org.apache.spark.SparkContext]] that returns [[org.apache.spark.api.java.JavaRDD]]s and
diff --git a/core/src/main/scala/org/apache/spark/api/python/PythonPartitioner.scala b/core/src/main/scala/org/apache/spark/api/python/PythonPartitioner.scala
index eea63d5a4e..b090c6edf3 100644
--- a/core/src/main/scala/org/apache/spark/api/python/PythonPartitioner.scala
+++ b/core/src/main/scala/org/apache/spark/api/python/PythonPartitioner.scala
@@ -18,8 +18,8 @@
 package org.apache.spark.api.python
 
 import org.apache.spark.Partitioner
-import org.apache.spark.Utils
 import java.util.Arrays
+import org.apache.spark.util.Utils
 
 /**
  * A [[org.apache.spark.Partitioner]] that performs handling of byte arrays, for use by the Python API.
diff --git a/core/src/main/scala/org/apache/spark/api/python/PythonRDD.scala b/core/src/main/scala/org/apache/spark/api/python/PythonRDD.scala
index 621f0fe8ee..ccd3833964 100644
--- a/core/src/main/scala/org/apache/spark/api/python/PythonRDD.scala
+++ b/core/src/main/scala/org/apache/spark/api/python/PythonRDD.scala
@@ -26,7 +26,9 @@ import scala.collection.JavaConversions._
 import org.apache.spark.api.java.{JavaSparkContext, JavaPairRDD, JavaRDD}
 import org.apache.spark.broadcast.Broadcast
 import org.apache.spark._
+import org.apache.spark.rdd.RDD
 import org.apache.spark.rdd.PipedRDD
+import org.apache.spark.util.Utils
 
 
 private[spark] class PythonRDD[T: ClassManifest](
diff --git a/core/src/main/scala/org/apache/spark/broadcast/BitTorrentBroadcast.scala b/core/src/main/scala/org/apache/spark/broadcast/BitTorrentBroadcast.scala
index 99e86237fc..93e7815ab5 100644
--- a/core/src/main/scala/org/apache/spark/broadcast/BitTorrentBroadcast.scala
+++ b/core/src/main/scala/org/apache/spark/broadcast/BitTorrentBroadcast.scala
@@ -27,6 +27,7 @@ import scala.math
 
 import org.apache.spark._
 import org.apache.spark.storage.StorageLevel
+import org.apache.spark.util.Utils
 
 private[spark] class BitTorrentBroadcast[T](@transient var value_ : T, isLocal: Boolean, id: Long)
   extends Broadcast[T](id)
diff --git a/core/src/main/scala/org/apache/spark/broadcast/HttpBroadcast.scala b/core/src/main/scala/org/apache/spark/broadcast/HttpBroadcast.scala
index 7a52ff0769..9db26ae6de 100644
--- a/core/src/main/scala/org/apache/spark/broadcast/HttpBroadcast.scala
+++ b/core/src/main/scala/org/apache/spark/broadcast/HttpBroadcast.scala
@@ -23,10 +23,10 @@ import java.net.URL
 import it.unimi.dsi.fastutil.io.FastBufferedInputStream
 import it.unimi.dsi.fastutil.io.FastBufferedOutputStream
 
-import org.apache.spark.{HttpServer, Logging, SparkEnv, Utils}
+import org.apache.spark.{HttpServer, Logging, SparkEnv}
 import org.apache.spark.io.CompressionCodec
 import org.apache.spark.storage.StorageLevel
-import org.apache.spark.util.{MetadataCleaner, TimeStampedHashSet}
+import org.apache.spark.util.{Utils, MetadataCleaner, TimeStampedHashSet}
 
 
 private[spark] class HttpBroadcast[T](@transient var value_ : T, isLocal: Boolean, id: Long)
diff --git a/core/src/main/scala/org/apache/spark/broadcast/MultiTracker.scala b/core/src/main/scala/org/apache/spark/broadcast/MultiTracker.scala
index 10b910df87..21ec94659e 100644
--- a/core/src/main/scala/org/apache/spark/broadcast/MultiTracker.scala
+++ b/core/src/main/scala/org/apache/spark/broadcast/MultiTracker.scala
@@ -24,6 +24,7 @@ import java.util.Random
 import scala.collection.mutable.Map
 
 import org.apache.spark._
+import org.apache.spark.util.Utils
 
 private object MultiTracker
 extends Logging {
diff --git a/core/src/main/scala/org/apache/spark/broadcast/TreeBroadcast.scala b/core/src/main/scala/org/apache/spark/broadcast/TreeBroadcast.scala
index b5a4ccc0ee..80c97ca073 100644
--- a/core/src/main/scala/org/apache/spark/broadcast/TreeBroadcast.scala
+++ b/core/src/main/scala/org/apache/spark/broadcast/TreeBroadcast.scala
@@ -26,6 +26,7 @@ import scala.math
 
 import org.apache.spark._
 import org.apache.spark.storage.StorageLevel
+import org.apache.spark.util.Utils
 
 private[spark] class TreeBroadcast[T](@transient var value_ : T, isLocal: Boolean, id: Long)
 extends Broadcast[T](id) with Logging with Serializable {
diff --git a/core/src/main/scala/org/apache/spark/deploy/DeployMessage.scala b/core/src/main/scala/org/apache/spark/deploy/DeployMessage.scala
index 4dc6ada2d1..c31619db27 100644
--- a/core/src/main/scala/org/apache/spark/deploy/DeployMessage.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/DeployMessage.scala
@@ -19,10 +19,10 @@ package org.apache.spark.deploy
 
 import scala.collection.immutable.List
 
-import org.apache.spark.Utils
 import org.apache.spark.deploy.ExecutorState.ExecutorState
 import org.apache.spark.deploy.master.{WorkerInfo, ApplicationInfo}
 import org.apache.spark.deploy.worker.ExecutorRunner
+import org.apache.spark.util.Utils
 
 
 private[deploy] sealed trait DeployMessage extends Serializable
diff --git a/core/src/main/scala/org/apache/spark/deploy/LocalSparkCluster.scala b/core/src/main/scala/org/apache/spark/deploy/LocalSparkCluster.scala
index af5a4110b0..78e3747ad8 100644
--- a/core/src/main/scala/org/apache/spark/deploy/LocalSparkCluster.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/LocalSparkCluster.scala
@@ -21,8 +21,8 @@ import akka.actor.{ActorRef, Props, Actor, ActorSystem, Terminated}
 
 import org.apache.spark.deploy.worker.Worker
 import org.apache.spark.deploy.master.Master
-import org.apache.spark.util.AkkaUtils
-import org.apache.spark.{Logging, Utils}
+import org.apache.spark.util.{Utils, AkkaUtils}
+import org.apache.spark.{Logging}
 
 import scala.collection.mutable.ArrayBuffer
 
diff --git a/core/src/main/scala/org/apache/spark/deploy/client/TestClient.scala b/core/src/main/scala/org/apache/spark/deploy/client/TestClient.scala
index 0322029fbd..d5e9a0e095 100644
--- a/core/src/main/scala/org/apache/spark/deploy/client/TestClient.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/client/TestClient.scala
@@ -17,8 +17,8 @@
 
 package org.apache.spark.deploy.client
 
-import org.apache.spark.util.AkkaUtils
-import org.apache.spark.{Logging, Utils}
+import org.apache.spark.util.{Utils, AkkaUtils}
+import org.apache.spark.{Logging}
 import org.apache.spark.deploy.{Command, ApplicationDescription}
 
 private[spark] object TestClient {
diff --git a/core/src/main/scala/org/apache/spark/deploy/master/Master.scala b/core/src/main/scala/org/apache/spark/deploy/master/Master.scala
index 869b2b2646..7cf0a7754f 100644
--- a/core/src/main/scala/org/apache/spark/deploy/master/Master.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/master/Master.scala
@@ -27,12 +27,12 @@ import akka.actor.Terminated
 import akka.remote.{RemoteClientLifeCycleEvent, RemoteClientDisconnected, RemoteClientShutdown}
 import akka.util.duration._
 
-import org.apache.spark.{Logging, SparkException, Utils}
+import org.apache.spark.{Logging, SparkException}
 import org.apache.spark.deploy.{ApplicationDescription, ExecutorState}
 import org.apache.spark.deploy.DeployMessages._
 import org.apache.spark.deploy.master.ui.MasterWebUI
 import org.apache.spark.metrics.MetricsSystem
-import org.apache.spark.util.AkkaUtils
+import org.apache.spark.util.{Utils, AkkaUtils}
 
 
 private[spark] class Master(host: String, port: Int, webUiPort: Int) extends Actor with Logging {
diff --git a/core/src/main/scala/org/apache/spark/deploy/master/MasterArguments.scala b/core/src/main/scala/org/apache/spark/deploy/master/MasterArguments.scala
index c86cca278d..9d89b455fb 100644
--- a/core/src/main/scala/org/apache/spark/deploy/master/MasterArguments.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/master/MasterArguments.scala
@@ -17,8 +17,7 @@
 
 package org.apache.spark.deploy.master
 
-import org.apache.spark.util.IntParam
-import org.apache.spark.Utils
+import org.apache.spark.util.{Utils, IntParam}
 
 /**
  * Command-line parser for the master.
diff --git a/core/src/main/scala/org/apache/spark/deploy/master/WorkerInfo.scala b/core/src/main/scala/org/apache/spark/deploy/master/WorkerInfo.scala
index 285e07a823..6219f11f2a 100644
--- a/core/src/main/scala/org/apache/spark/deploy/master/WorkerInfo.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/master/WorkerInfo.scala
@@ -19,7 +19,7 @@ package org.apache.spark.deploy.master
 
 import akka.actor.ActorRef
 import scala.collection.mutable
-import org.apache.spark.Utils
+import org.apache.spark.util.Utils
 
 private[spark] class WorkerInfo(
   val id: String,
diff --git a/core/src/main/scala/org/apache/spark/deploy/master/ui/ApplicationPage.scala b/core/src/main/scala/org/apache/spark/deploy/master/ui/ApplicationPage.scala
index 6435c7f917..f4e574d15d 100644
--- a/core/src/main/scala/org/apache/spark/deploy/master/ui/ApplicationPage.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/master/ui/ApplicationPage.scala
@@ -31,7 +31,7 @@ import org.apache.spark.deploy.DeployMessages.{MasterStateResponse, RequestMaste
 import org.apache.spark.deploy.JsonProtocol
 import org.apache.spark.deploy.master.ExecutorInfo
 import org.apache.spark.ui.UIUtils
-import org.apache.spark.Utils
+import org.apache.spark.util.Utils
 
 private[spark] class ApplicationPage(parent: MasterWebUI) {
   val master = parent.masterActorRef
diff --git a/core/src/main/scala/org/apache/spark/deploy/master/ui/IndexPage.scala b/core/src/main/scala/org/apache/spark/deploy/master/ui/IndexPage.scala
index 58d3863009..d7a57229b0 100644
--- a/core/src/main/scala/org/apache/spark/deploy/master/ui/IndexPage.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/master/ui/IndexPage.scala
@@ -27,12 +27,12 @@ import akka.util.duration._
 
 import net.liftweb.json.JsonAST.JValue
 
-import org.apache.spark.Utils
 import org.apache.spark.deploy.DeployWebUI
 import org.apache.spark.deploy.DeployMessages.{MasterStateResponse, RequestMasterState}
 import org.apache.spark.deploy.JsonProtocol
 import org.apache.spark.deploy.master.{ApplicationInfo, WorkerInfo}
 import org.apache.spark.ui.UIUtils
+import org.apache.spark.util.Utils
 
 private[spark] class IndexPage(parent: MasterWebUI) {
   val master = parent.masterActorRef
diff --git a/core/src/main/scala/org/apache/spark/deploy/master/ui/MasterWebUI.scala b/core/src/main/scala/org/apache/spark/deploy/master/ui/MasterWebUI.scala
index 47b1e521f5..f4df729e87 100644
--- a/core/src/main/scala/org/apache/spark/deploy/master/ui/MasterWebUI.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/master/ui/MasterWebUI.scala
@@ -23,10 +23,11 @@ import javax.servlet.http.HttpServletRequest
 
 import org.eclipse.jetty.server.{Handler, Server}
 
-import org.apache.spark.{Logging, Utils}
+import org.apache.spark.{Logging}
 import org.apache.spark.deploy.master.Master
 import org.apache.spark.ui.JettyUtils
 import org.apache.spark.ui.JettyUtils._
+import org.apache.spark.util.Utils
 
 /**
  * Web UI server for the standalone master.
diff --git a/core/src/main/scala/org/apache/spark/deploy/worker/ExecutorRunner.scala b/core/src/main/scala/org/apache/spark/deploy/worker/ExecutorRunner.scala
index 01ce4a6dea..e3dc30eefc 100644
--- a/core/src/main/scala/org/apache/spark/deploy/worker/ExecutorRunner.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/worker/ExecutorRunner.scala
@@ -25,9 +25,10 @@ import akka.actor.ActorRef
 import com.google.common.base.Charsets
 import com.google.common.io.Files
 
-import org.apache.spark.{Utils, Logging}
+import org.apache.spark.{Logging}
 import org.apache.spark.deploy.{ExecutorState, ApplicationDescription}
 import org.apache.spark.deploy.DeployMessages.ExecutorStateChanged
+import org.apache.spark.util.Utils
 
 /**
  * Manages the execution of one executor process.
diff --git a/core/src/main/scala/org/apache/spark/deploy/worker/Worker.scala b/core/src/main/scala/org/apache/spark/deploy/worker/Worker.scala
index 86e8e7543b..09530beb3b 100644
--- a/core/src/main/scala/org/apache/spark/deploy/worker/Worker.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/worker/Worker.scala
@@ -27,13 +27,13 @@ import akka.actor.{ActorRef, Props, Actor, ActorSystem, Terminated}
 import akka.remote.{RemoteClientLifeCycleEvent, RemoteClientShutdown, RemoteClientDisconnected}
 import akka.util.duration._
 
-import org.apache.spark.{Logging, Utils}
+import org.apache.spark.{Logging}
 import org.apache.spark.deploy.ExecutorState
 import org.apache.spark.deploy.DeployMessages._
 import org.apache.spark.deploy.master.Master
 import org.apache.spark.deploy.worker.ui.WorkerWebUI
 import org.apache.spark.metrics.MetricsSystem
-import org.apache.spark.util.AkkaUtils
+import org.apache.spark.util.{Utils, AkkaUtils}
 
 
 private[spark] class Worker(
diff --git a/core/src/main/scala/org/apache/spark/deploy/worker/WorkerArguments.scala b/core/src/main/scala/org/apache/spark/deploy/worker/WorkerArguments.scala
index 6d91223413..0ae89a864f 100644
--- a/core/src/main/scala/org/apache/spark/deploy/worker/WorkerArguments.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/worker/WorkerArguments.scala
@@ -17,9 +17,7 @@
 
 package org.apache.spark.deploy.worker
 
-import org.apache.spark.util.IntParam
-import org.apache.spark.util.MemoryParam
-import org.apache.spark.Utils
+import org.apache.spark.util.{Utils, IntParam, MemoryParam}
 import java.lang.management.ManagementFactory
 
 /**
diff --git a/core/src/main/scala/org/apache/spark/deploy/worker/ui/IndexPage.scala b/core/src/main/scala/org/apache/spark/deploy/worker/ui/IndexPage.scala
index 6192c2324b..d2d3617498 100644
--- a/core/src/main/scala/org/apache/spark/deploy/worker/ui/IndexPage.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/worker/ui/IndexPage.scala
@@ -27,11 +27,11 @@ import akka.util.duration._
 
 import net.liftweb.json.JsonAST.JValue
 
-import org.apache.spark.Utils
 import org.apache.spark.deploy.JsonProtocol
 import org.apache.spark.deploy.DeployMessages.{RequestWorkerState, WorkerStateResponse}
 import org.apache.spark.deploy.worker.ExecutorRunner
 import org.apache.spark.ui.UIUtils
+import org.apache.spark.util.Utils
 
 
 private[spark] class IndexPage(parent: WorkerWebUI) {
diff --git a/core/src/main/scala/org/apache/spark/deploy/worker/ui/WorkerWebUI.scala b/core/src/main/scala/org/apache/spark/deploy/worker/ui/WorkerWebUI.scala
index bb8165ac09..95d6007f3b 100644
--- a/core/src/main/scala/org/apache/spark/deploy/worker/ui/WorkerWebUI.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/worker/ui/WorkerWebUI.scala
@@ -26,10 +26,11 @@ import javax.servlet.http.HttpServletRequest
 import org.eclipse.jetty.server.{Handler, Server}
 
 import org.apache.spark.deploy.worker.Worker
-import org.apache.spark.{Utils, Logging}
+import org.apache.spark.{Logging}
 import org.apache.spark.ui.JettyUtils
 import org.apache.spark.ui.JettyUtils._
 import org.apache.spark.ui.UIUtils
+import org.apache.spark.util.Utils
 
 /**
  * Web UI server for the standalone worker.
diff --git a/core/src/main/scala/org/apache/spark/executor/Executor.scala b/core/src/main/scala/org/apache/spark/executor/Executor.scala
index 5446a3fca9..d365804994 100644
--- a/core/src/main/scala/org/apache/spark/executor/Executor.scala
+++ b/core/src/main/scala/org/apache/spark/executor/Executor.scala
@@ -27,6 +27,7 @@ import scala.collection.mutable.HashMap
 
 import org.apache.spark.scheduler._
 import org.apache.spark._
+import org.apache.spark.util.Utils
 
 
 /**
diff --git a/core/src/main/scala/org/apache/spark/executor/MesosExecutorBackend.scala b/core/src/main/scala/org/apache/spark/executor/MesosExecutorBackend.scala
index 410a94df6b..da62091980 100644
--- a/core/src/main/scala/org/apache/spark/executor/MesosExecutorBackend.scala
+++ b/core/src/main/scala/org/apache/spark/executor/MesosExecutorBackend.scala
@@ -22,8 +22,9 @@ import org.apache.mesos.{Executor => MesosExecutor, MesosExecutorDriver, MesosNa
 import org.apache.mesos.Protos.{TaskState => MesosTaskState, TaskStatus => MesosTaskStatus, _}
 import org.apache.spark.TaskState.TaskState
 import com.google.protobuf.ByteString
-import org.apache.spark.{Utils, Logging}
+import org.apache.spark.{Logging}
 import org.apache.spark.TaskState
+import org.apache.spark.util.Utils
 
 private[spark] class MesosExecutorBackend
   extends MesosExecutor
diff --git a/core/src/main/scala/org/apache/spark/executor/StandaloneExecutorBackend.scala b/core/src/main/scala/org/apache/spark/executor/StandaloneExecutorBackend.scala
index 65801f75b7..7839023868 100644
--- a/core/src/main/scala/org/apache/spark/executor/StandaloneExecutorBackend.scala
+++ b/core/src/main/scala/org/apache/spark/executor/StandaloneExecutorBackend.scala
@@ -22,10 +22,10 @@ import java.nio.ByteBuffer
 import akka.actor.{ActorRef, Actor, Props, Terminated}
 import akka.remote.{RemoteClientLifeCycleEvent, RemoteClientShutdown, RemoteClientDisconnected}
 
-import org.apache.spark.{Logging, Utils, SparkEnv}
+import org.apache.spark.{Logging, SparkEnv}
 import org.apache.spark.TaskState.TaskState
 import org.apache.spark.scheduler.cluster.StandaloneClusterMessages._
-import org.apache.spark.util.AkkaUtils
+import org.apache.spark.util.{Utils, AkkaUtils}
 
 
 private[spark] class StandaloneExecutorBackend(
diff --git a/core/src/main/scala/org/apache/spark/network/ConnectionManager.scala b/core/src/main/scala/org/apache/spark/network/ConnectionManager.scala
index 9e2233c07b..e15a839c4e 100644
--- a/core/src/main/scala/org/apache/spark/network/ConnectionManager.scala
+++ b/core/src/main/scala/org/apache/spark/network/ConnectionManager.scala
@@ -34,6 +34,7 @@ import scala.collection.mutable.ArrayBuffer
 import akka.dispatch.{Await, Promise, ExecutionContext, Future}
 import akka.util.Duration
 import akka.util.duration._
+import org.apache.spark.util.Utils
 
 
 private[spark] class ConnectionManager(port: Int) extends Logging {
diff --git a/core/src/main/scala/org/apache/spark/network/ConnectionManagerId.scala b/core/src/main/scala/org/apache/spark/network/ConnectionManagerId.scala
index 0839c011b8..50dd9bc2d1 100644
--- a/core/src/main/scala/org/apache/spark/network/ConnectionManagerId.scala
+++ b/core/src/main/scala/org/apache/spark/network/ConnectionManagerId.scala
@@ -19,7 +19,7 @@ package org.apache.spark.network
 
 import java.net.InetSocketAddress
 
-import org.apache.spark.Utils
+import org.apache.spark.util.Utils
 
 
 private[spark] case class ConnectionManagerId(host: String, port: Int) {
diff --git a/core/src/main/scala/org/apache/spark/package.scala b/core/src/main/scala/org/apache/spark/package.scala
index 1126480689..c0ec527339 100644
--- a/core/src/main/scala/org/apache/spark/package.scala
+++ b/core/src/main/scala/org/apache/spark/package.scala
@@ -1,3 +1,5 @@
+import org.apache.spark.rdd.{SequenceFileRDDFunctions, DoubleRDDFunctions, PairRDDFunctions}
+
 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
@@ -16,16 +18,17 @@
  */
 
 /**
- * Core Spark functionality. [[org.apache.spark.SparkContext]] serves as the main entry point to Spark, while
- * [[org.apache.spark.RDD]] is the data type representing a distributed collection, and provides most
- * parallel operations. 
+ * Core Spark functionality. [[org.apache.spark.SparkContext]] serves as the main entry point to
+ * Spark, while [[org.apache.spark.rdd.RDD]] is the data type representing a distributed collection,
+ * and provides most parallel operations.
  *
- * In addition, [[org.apache.spark.PairRDDFunctions]] contains operations available only on RDDs of key-value
- * pairs, such as `groupByKey` and `join`; [[org.apache.spark.DoubleRDDFunctions]] contains operations
- * available only on RDDs of Doubles; and [[org.apache.spark.SequenceFileRDDFunctions]] contains operations
- * available on RDDs that can be saved as SequenceFiles. These operations are automatically
- * available on any RDD of the right type (e.g. RDD[(Int, Int)] through implicit conversions when
- * you `import org.apache.spark.SparkContext._`.
+ * In addition, [[org.apache.spark.rdd.PairRDDFunctions]] contains operations available only on RDDs
+ * of key-value pairs, such as `groupByKey` and `join`; [[org.apache.spark.rdd.DoubleRDDFunctions]]
+ * contains operations available only on RDDs of Doubles; and
+ * [[org.apache.spark.rdd.SequenceFileRDDFunctions]] contains operations available on RDDs that can
+ * be saved as SequenceFiles. These operations are automatically available on any RDD of the right
+ * type (e.g. RDD[(Int, Int)] through implicit conversions when you
+ * `import org.apache.spark.SparkContext._`.
  */
 package object spark { 
   // For package docs only
diff --git a/core/src/main/scala/org/apache/spark/partial/ApproximateActionListener.scala b/core/src/main/scala/org/apache/spark/partial/ApproximateActionListener.scala
index c5d51bee50..d71069444a 100644
--- a/core/src/main/scala/org/apache/spark/partial/ApproximateActionListener.scala
+++ b/core/src/main/scala/org/apache/spark/partial/ApproximateActionListener.scala
@@ -19,6 +19,7 @@ package org.apache.spark.partial
 
 import org.apache.spark._
 import org.apache.spark.scheduler.JobListener
+import org.apache.spark.rdd.RDD
 
 /**
  * A JobListener for an approximate single-result action, such as count() or non-parallel reduce().
diff --git a/core/src/main/scala/org/apache/spark/rdd/BlockRDD.scala b/core/src/main/scala/org/apache/spark/rdd/BlockRDD.scala
index 4bb01efa86..bca6956a18 100644
--- a/core/src/main/scala/org/apache/spark/rdd/BlockRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/BlockRDD.scala
@@ -17,7 +17,7 @@
 
 package org.apache.spark.rdd
 
-import org.apache.spark.{RDD, SparkContext, SparkEnv, Partition, TaskContext}
+import org.apache.spark.{SparkContext, SparkEnv, Partition, TaskContext}
 import org.apache.spark.storage.BlockManager
 
 private[spark] class BlockRDDPartition(val blockId: String, idx: Int) extends Partition {
diff --git a/core/src/main/scala/org/apache/spark/rdd/CoGroupedRDD.scala b/core/src/main/scala/org/apache/spark/rdd/CoGroupedRDD.scala
index dcc35e8d0e..0187256a8e 100644
--- a/core/src/main/scala/org/apache/spark/rdd/CoGroupedRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/CoGroupedRDD.scala
@@ -23,7 +23,7 @@ import java.util.{HashMap => JHashMap}
 import scala.collection.JavaConversions
 import scala.collection.mutable.ArrayBuffer
 
-import org.apache.spark.{Partition, Partitioner, RDD, SparkEnv, TaskContext}
+import org.apache.spark.{Partition, Partitioner, SparkEnv, TaskContext}
 import org.apache.spark.{Dependency, OneToOneDependency, ShuffleDependency}
 
 
diff --git a/core/src/main/scala/org/apache/spark/DoubleRDDFunctions.scala b/core/src/main/scala/org/apache/spark/rdd/DoubleRDDFunctions.scala
index dd344491b8..a4bec41752 100644
--- a/core/src/main/scala/org/apache/spark/DoubleRDDFunctions.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/DoubleRDDFunctions.scala
@@ -15,17 +15,18 @@
  * limitations under the License.
  */
 
-package org.apache.spark
+package org.apache.spark.rdd
 
 import org.apache.spark.partial.BoundedDouble
 import org.apache.spark.partial.MeanEvaluator
 import org.apache.spark.partial.PartialResult
 import org.apache.spark.partial.SumEvaluator
 import org.apache.spark.util.StatCounter
+import org.apache.spark.{TaskContext, Logging}
 
 /**
  * Extra functions available on RDDs of Doubles through an implicit conversion.
- * Import `spark.SparkContext._` at the top of your program to use these functions.
+ * Import `org.apache.spark.SparkContext._` at the top of your program to use these functions.
  */
 class DoubleRDDFunctions(self: RDD[Double]) extends Logging with Serializable {
   /** Add up the elements in this RDD. */
diff --git a/core/src/main/scala/org/apache/spark/rdd/EmptyRDD.scala b/core/src/main/scala/org/apache/spark/rdd/EmptyRDD.scala
index 24ce4abbc4..c8900d1a93 100644
--- a/core/src/main/scala/org/apache/spark/rdd/EmptyRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/EmptyRDD.scala
@@ -17,7 +17,7 @@
 
 package org.apache.spark.rdd
 
-import org.apache.spark.{RDD, SparkContext, SparkEnv, Partition, TaskContext}
+import org.apache.spark.{SparkContext, SparkEnv, Partition, TaskContext}
 
 
 /**
diff --git a/core/src/main/scala/org/apache/spark/rdd/FilteredRDD.scala b/core/src/main/scala/org/apache/spark/rdd/FilteredRDD.scala
index 4df8ceb58b..5312dc0b59 100644
--- a/core/src/main/scala/org/apache/spark/rdd/FilteredRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/FilteredRDD.scala
@@ -17,7 +17,7 @@
 
 package org.apache.spark.rdd
 
-import org.apache.spark.{OneToOneDependency, RDD, Partition, TaskContext}
+import org.apache.spark.{OneToOneDependency, Partition, TaskContext}
 
 private[spark] class FilteredRDD[T: ClassManifest](
     prev: RDD[T],
diff --git a/core/src/main/scala/org/apache/spark/rdd/FlatMappedRDD.scala b/core/src/main/scala/org/apache/spark/rdd/FlatMappedRDD.scala
index 2bf7653af1..cbdf6d84c0 100644
--- a/core/src/main/scala/org/apache/spark/rdd/FlatMappedRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/FlatMappedRDD.scala
@@ -17,7 +17,7 @@
 
 package org.apache.spark.rdd
 
-import org.apache.spark.{RDD, Partition, TaskContext}
+import org.apache.spark.{Partition, TaskContext}
 
 
 private[spark]
diff --git a/core/src/main/scala/org/apache/spark/rdd/FlatMappedValuesRDD.scala b/core/src/main/scala/org/apache/spark/rdd/FlatMappedValuesRDD.scala
index e544720b05..82000bac09 100644
--- a/core/src/main/scala/org/apache/spark/rdd/FlatMappedValuesRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/FlatMappedValuesRDD.scala
@@ -17,7 +17,7 @@
 
 package org.apache.spark.rdd
 
-import org.apache.spark.{TaskContext, Partition, RDD}
+import org.apache.spark.{TaskContext, Partition}
 
 
 private[spark]
diff --git a/core/src/main/scala/org/apache/spark/rdd/GlommedRDD.scala b/core/src/main/scala/org/apache/spark/rdd/GlommedRDD.scala
index 2ce94199f2..829545d7b0 100644
--- a/core/src/main/scala/org/apache/spark/rdd/GlommedRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/GlommedRDD.scala
@@ -17,7 +17,7 @@
 
 package org.apache.spark.rdd
 
-import org.apache.spark.{RDD, Partition, TaskContext}
+import org.apache.spark.{Partition, TaskContext}
 
 private[spark] class GlommedRDD[T: ClassManifest](prev: RDD[T])
   extends RDD[Array[T]](prev) {
diff --git a/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala b/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala
index 08e6154bb9..2cb6734e41 100644
--- a/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala
@@ -18,21 +18,15 @@
 package org.apache.spark.rdd
 
 import java.io.EOFException
-import java.util.NoSuchElementException
 
-import org.apache.hadoop.io.LongWritable
-import org.apache.hadoop.io.NullWritable
-import org.apache.hadoop.io.Text
-import org.apache.hadoop.mapred.FileInputFormat
 import org.apache.hadoop.mapred.InputFormat
 import org.apache.hadoop.mapred.InputSplit
 import org.apache.hadoop.mapred.JobConf
-import org.apache.hadoop.mapred.TextInputFormat
 import org.apache.hadoop.mapred.RecordReader
 import org.apache.hadoop.mapred.Reporter
 import org.apache.hadoop.util.ReflectionUtils
 
-import org.apache.spark.{Dependency, Logging, Partition, RDD, SerializableWritable, SparkContext, SparkEnv, TaskContext}
+import org.apache.spark.{Logging, Partition, SerializableWritable, SparkContext, SparkEnv, TaskContext}
 import org.apache.spark.util.NextIterator
 import org.apache.hadoop.conf.{Configuration, Configurable}
 
diff --git a/core/src/main/scala/org/apache/spark/rdd/JdbcRDD.scala b/core/src/main/scala/org/apache/spark/rdd/JdbcRDD.scala
index 3db460b3ce..aca0146884 100644
--- a/core/src/main/scala/org/apache/spark/rdd/JdbcRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/JdbcRDD.scala
@@ -19,7 +19,7 @@ package org.apache.spark.rdd
 
 import java.sql.{Connection, ResultSet}
 
-import org.apache.spark.{Logging, Partition, RDD, SparkContext, TaskContext}
+import org.apache.spark.{Logging, Partition, SparkContext, TaskContext}
 import org.apache.spark.util.NextIterator
 
 private[spark] class JdbcPartition(idx: Int, val lower: Long, val upper: Long) extends Partition {
diff --git a/core/src/main/scala/org/apache/spark/rdd/MapPartitionsRDD.scala b/core/src/main/scala/org/apache/spark/rdd/MapPartitionsRDD.scala
index 13009d3e17..203179c4ea 100644
--- a/core/src/main/scala/org/apache/spark/rdd/MapPartitionsRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/MapPartitionsRDD.scala
@@ -17,7 +17,7 @@
 
 package org.apache.spark.rdd
 
-import org.apache.spark.{RDD, Partition, TaskContext}
+import org.apache.spark.{Partition, TaskContext}
 
 
 private[spark]
diff --git a/core/src/main/scala/org/apache/spark/rdd/MapPartitionsWithIndexRDD.scala b/core/src/main/scala/org/apache/spark/rdd/MapPartitionsWithIndexRDD.scala
index 1683050b86..3ed8339010 100644
--- a/core/src/main/scala/org/apache/spark/rdd/MapPartitionsWithIndexRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/MapPartitionsWithIndexRDD.scala
@@ -17,7 +17,7 @@
 
 package org.apache.spark.rdd
 
-import org.apache.spark.{RDD, Partition, TaskContext}
+import org.apache.spark.{Partition, TaskContext}
 
 
 /**
diff --git a/core/src/main/scala/org/apache/spark/rdd/MappedRDD.scala b/core/src/main/scala/org/apache/spark/rdd/MappedRDD.scala
index 26d4806edb..e8be1c4816 100644
--- a/core/src/main/scala/org/apache/spark/rdd/MappedRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/MappedRDD.scala
@@ -17,7 +17,7 @@
 
 package org.apache.spark.rdd
 
-import org.apache.spark.{RDD, Partition, TaskContext}
+import org.apache.spark.{Partition, TaskContext}
 
 private[spark]
 class MappedRDD[U: ClassManifest, T: ClassManifest](prev: RDD[T], f: T => U)
diff --git a/core/src/main/scala/org/apache/spark/rdd/MappedValuesRDD.scala b/core/src/main/scala/org/apache/spark/rdd/MappedValuesRDD.scala
index a405e9acdd..d33c1af581 100644
--- a/core/src/main/scala/org/apache/spark/rdd/MappedValuesRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/MappedValuesRDD.scala
@@ -18,7 +18,7 @@
 package org.apache.spark.rdd
 
 
-import org.apache.spark.{TaskContext, Partition, RDD}
+import org.apache.spark.{TaskContext, Partition}
 
 private[spark]
 class MappedValuesRDD[K, V, U](prev: RDD[_ <: Product2[K, V]], f: V => U)
diff --git a/core/src/main/scala/org/apache/spark/rdd/NewHadoopRDD.scala b/core/src/main/scala/org/apache/spark/rdd/NewHadoopRDD.scala
index 114b504486..7b3a89f7e0 100644
--- a/core/src/main/scala/org/apache/spark/rdd/NewHadoopRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/NewHadoopRDD.scala
@@ -24,7 +24,7 @@ import org.apache.hadoop.conf.{Configurable, Configuration}
 import org.apache.hadoop.io.Writable
 import org.apache.hadoop.mapreduce._
 
-import org.apache.spark.{Dependency, Logging, Partition, RDD, SerializableWritable, SparkContext, TaskContext}
+import org.apache.spark.{Dependency, Logging, Partition, SerializableWritable, SparkContext, TaskContext}
 
 
 private[spark]
diff --git a/core/src/main/scala/org/apache/spark/rdd/OrderedRDDFunctions.scala b/core/src/main/scala/org/apache/spark/rdd/OrderedRDDFunctions.scala
index 4c3df0eaf4..697be8b997 100644
--- a/core/src/main/scala/org/apache/spark/rdd/OrderedRDDFunctions.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/OrderedRDDFunctions.scala
@@ -17,12 +17,13 @@
 
 package org.apache.spark.rdd
 
-import org.apache.spark.{RangePartitioner, Logging, RDD}
+import org.apache.spark.{RangePartitioner, Logging}
 
 /**
  * Extra functions available on RDDs of (key, value) pairs where the key is sortable through
- * an implicit conversion. Import `spark.SparkContext._` at the top of your program to use these
- * functions. They will work with any key type that has a `scala.math.Ordered` implementation.
+ * an implicit conversion. Import `org.apache.spark.SparkContext._` at the top of your program to
+ * use these functions. They will work with any key type that has a `scala.math.Ordered`
+ * implementation.
  */
 class OrderedRDDFunctions[K <% Ordered[K]: ClassManifest,
                           V: ClassManifest,
diff --git a/core/src/main/scala/org/apache/spark/PairRDDFunctions.scala b/core/src/main/scala/org/apache/spark/rdd/PairRDDFunctions.scala
index d046e7c1a4..a47c512275 100644
--- a/core/src/main/scala/org/apache/spark/PairRDDFunctions.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/PairRDDFunctions.scala
@@ -15,40 +15,40 @@
  * limitations under the License.
  */
 
-package org.apache.spark
+package org.apache.spark.rdd
 
 import java.nio.ByteBuffer
-import java.util.{Date, HashMap => JHashMap}
+import java.util.Date
 import java.text.SimpleDateFormat
+import java.util.{HashMap => JHashMap}
 
 import scala.collection.{mutable, Map}
 import scala.collection.mutable.ArrayBuffer
 import scala.collection.JavaConversions._
 
+import org.apache.hadoop.mapred._
+import org.apache.hadoop.io.compress.CompressionCodec
 import org.apache.hadoop.conf.Configuration
 import org.apache.hadoop.fs.Path
-import org.apache.hadoop.io.compress.CompressionCodec
 import org.apache.hadoop.io.SequenceFile.CompressionType
-import org.apache.hadoop.mapred.FileOutputCommitter
 import org.apache.hadoop.mapred.FileOutputFormat
-import org.apache.hadoop.mapred.SparkHadoopWriter
-import org.apache.hadoop.mapred.JobConf
 import org.apache.hadoop.mapred.OutputFormat
-
+import org.apache.hadoop.mapreduce.{OutputFormat => NewOutputFormat}
 import org.apache.hadoop.mapreduce.lib.output.{FileOutputFormat => NewFileOutputFormat}
-import org.apache.hadoop.mapreduce.{OutputFormat => NewOutputFormat,
-    RecordWriter => NewRecordWriter, Job => NewAPIHadoopJob, SparkHadoopMapReduceUtil}
-import org.apache.hadoop.security.UserGroupInformation
+import org.apache.hadoop.mapreduce.SparkHadoopMapReduceUtil
+import org.apache.hadoop.mapreduce.{Job => NewAPIHadoopJob}
+import org.apache.hadoop.mapreduce.{RecordWriter => NewRecordWriter}
 
-import org.apache.spark.partial.BoundedDouble
-import org.apache.spark.partial.PartialResult
-import org.apache.spark.rdd._
+import org.apache.spark._
 import org.apache.spark.SparkContext._
-import org.apache.spark.Partitioner._
+import org.apache.spark.partial.{BoundedDouble, PartialResult}
+import org.apache.spark.Aggregator
+import org.apache.spark.Partitioner
+import org.apache.spark.Partitioner.defaultPartitioner
 
 /**
  * Extra functions available on RDDs of (key, value) pairs through an implicit conversion.
- * Import `spark.SparkContext._` at the top of your program to use these functions.
+ * Import `org.apache.spark.SparkContext._` at the top of your program to use these functions.
  */
 class PairRDDFunctions[K: ClassManifest, V: ClassManifest](self: RDD[(K, V)])
   extends Logging
@@ -697,7 +697,6 @@ class PairRDDFunctions[K: ClassManifest, V: ClassManifest](self: RDD[(K, V)])
   private[spark] def getValueClass() = implicitly[ClassManifest[V]].erasure
 }
 
-
 private[spark] object Manifests {
   val seqSeqManifest = classManifest[Seq[Seq[_]]]
 }
diff --git a/core/src/main/scala/org/apache/spark/rdd/ParallelCollectionRDD.scala b/core/src/main/scala/org/apache/spark/rdd/ParallelCollectionRDD.scala
index 8db3611054..6dbd4309aa 100644
--- a/core/src/main/scala/org/apache/spark/rdd/ParallelCollectionRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/ParallelCollectionRDD.scala
@@ -23,6 +23,8 @@ import scala.collection.Map
 import org.apache.spark._
 import java.io._
 import scala.Serializable
+import org.apache.spark.serializer.JavaSerializer
+import org.apache.spark.util.Utils
 
 private[spark] class ParallelCollectionPartition[T: ClassManifest](
     var rddId: Long,
diff --git a/core/src/main/scala/org/apache/spark/rdd/PartitionPruningRDD.scala b/core/src/main/scala/org/apache/spark/rdd/PartitionPruningRDD.scala
index 8e79a5c874..165cd412fc 100644
--- a/core/src/main/scala/org/apache/spark/rdd/PartitionPruningRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/PartitionPruningRDD.scala
@@ -17,7 +17,7 @@
 
 package org.apache.spark.rdd
 
-import org.apache.spark.{NarrowDependency, RDD, SparkEnv, Partition, TaskContext}
+import org.apache.spark.{NarrowDependency, SparkEnv, Partition, TaskContext}
 
 
 class PartitionPruningRDDPartition(idx: Int, val parentSplit: Partition) extends Partition {
diff --git a/core/src/main/scala/org/apache/spark/rdd/PipedRDD.scala b/core/src/main/scala/org/apache/spark/rdd/PipedRDD.scala
index 98498d5ddf..d5304ab0ae 100644
--- a/core/src/main/scala/org/apache/spark/rdd/PipedRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/PipedRDD.scala
@@ -25,7 +25,7 @@ import scala.collection.JavaConversions._
 import scala.collection.mutable.ArrayBuffer
 import scala.io.Source
 
-import org.apache.spark.{RDD, SparkEnv, Partition, TaskContext}
+import org.apache.spark.{SparkEnv, Partition, TaskContext}
 import org.apache.spark.broadcast.Broadcast
 
 
diff --git a/core/src/main/scala/org/apache/spark/RDD.scala b/core/src/main/scala/org/apache/spark/rdd/RDD.scala
index 0d1f07f76c..e143ecd096 100644
--- a/core/src/main/scala/org/apache/spark/RDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/RDD.scala
@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark
+package org.apache.spark.rdd
 
 import java.util.Random
 
@@ -37,37 +37,22 @@ import org.apache.spark.partial.BoundedDouble
 import org.apache.spark.partial.CountEvaluator
 import org.apache.spark.partial.GroupedCountEvaluator
 import org.apache.spark.partial.PartialResult
-import org.apache.spark.rdd.CoalescedRDD
-import org.apache.spark.rdd.CartesianRDD
-import org.apache.spark.rdd.FilteredRDD
-import org.apache.spark.rdd.FlatMappedRDD
-import org.apache.spark.rdd.GlommedRDD
-import org.apache.spark.rdd.MappedRDD
-import org.apache.spark.rdd.MapPartitionsRDD
-import org.apache.spark.rdd.MapPartitionsWithIndexRDD
-import org.apache.spark.rdd.PipedRDD
-import org.apache.spark.rdd.SampledRDD
-import org.apache.spark.rdd.ShuffledRDD
-import org.apache.spark.rdd.UnionRDD
-import org.apache.spark.rdd.ZippedRDD
-import org.apache.spark.rdd.ZippedPartitionsRDD2
-import org.apache.spark.rdd.ZippedPartitionsRDD3
-import org.apache.spark.rdd.ZippedPartitionsRDD4
 import org.apache.spark.storage.StorageLevel
-import org.apache.spark.util.BoundedPriorityQueue
+import org.apache.spark.util.{Utils, BoundedPriorityQueue}
 
-import SparkContext._
+import org.apache.spark.SparkContext._
+import org.apache.spark._
 
 /**
  * A Resilient Distributed Dataset (RDD), the basic abstraction in Spark. Represents an immutable,
  * partitioned collection of elements that can be operated on in parallel. This class contains the
  * basic operations available on all RDDs, such as `map`, `filter`, and `persist`. In addition,
- * [[org.apache.spark.PairRDDFunctions]] contains operations available only on RDDs of key-value pairs, such
- * as `groupByKey` and `join`; [[org.apache.spark.DoubleRDDFunctions]] contains operations available only on
- * RDDs of Doubles; and [[org.apache.spark.SequenceFileRDDFunctions]] contains operations available on RDDs
- * that can be saved as SequenceFiles. These operations are automatically available on any RDD of
- * the right type (e.g. RDD[(Int, Int)] through implicit conversions when you
- * `import org.apache.spark.SparkContext._`.
+ * [[org.apache.spark.rdd.PairRDDFunctions]] contains operations available only on RDDs of key-value
+ * pairs, such as `groupByKey` and `join`; [[org.apache.spark.rdd.DoubleRDDFunctions]] contains
+ * operations available only on RDDs of Doubles; and [[org.apache.spark.rdd.SequenceFileRDDFunctions]]
+ * contains operations available on RDDs that can be saved as SequenceFiles. These operations are
+ * automatically available on any RDD of the right type (e.g. RDD[(Int, Int)] through implicit
+ * conversions when you `import org.apache.spark.SparkContext._`.
  *
  * Internally, each RDD is characterized by five main properties:
  *
diff --git a/core/src/main/scala/org/apache/spark/RDDCheckpointData.scala b/core/src/main/scala/org/apache/spark/rdd/RDDCheckpointData.scala
index 0334de6924..6009a41570 100644
--- a/core/src/main/scala/org/apache/spark/RDDCheckpointData.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/RDDCheckpointData.scala
@@ -15,12 +15,13 @@
  * limitations under the License.
  */
 
-package org.apache.spark
+package org.apache.spark.rdd
 
 import org.apache.hadoop.fs.Path
 import org.apache.hadoop.conf.Configuration
-import rdd.{CheckpointRDD, CoalescedRDD}
-import scheduler.{ResultTask, ShuffleMapTask}
+
+import org.apache.spark.{Partition, SparkException, Logging}
+import org.apache.spark.scheduler.{ResultTask, ShuffleMapTask}
 
 /**
  * Enumeration to manage state transitions of an RDD through checkpointing
diff --git a/core/src/main/scala/org/apache/spark/rdd/SampledRDD.scala b/core/src/main/scala/org/apache/spark/rdd/SampledRDD.scala
index 1e8d89e912..2c5253ae30 100644
--- a/core/src/main/scala/org/apache/spark/rdd/SampledRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/SampledRDD.scala
@@ -22,7 +22,7 @@ import java.util.Random
 import cern.jet.random.Poisson
 import cern.jet.random.engine.DRand
 
-import org.apache.spark.{RDD, Partition, TaskContext}
+import org.apache.spark.{Partition, TaskContext}
 
 private[spark]
 class SampledRDDPartition(val prev: Partition, val seed: Int) extends Partition with Serializable {
diff --git a/core/src/main/scala/org/apache/spark/SequenceFileRDDFunctions.scala b/core/src/main/scala/org/apache/spark/rdd/SequenceFileRDDFunctions.scala
index d58fb4e4bc..5fe4676029 100644
--- a/core/src/main/scala/org/apache/spark/SequenceFileRDDFunctions.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/SequenceFileRDDFunctions.scala
@@ -15,40 +15,22 @@
  * limitations under the License.
  */
 
-package org.apache.spark
-
-import java.io.EOFException
-import java.net.URL
-import java.io.ObjectInputStream
-import java.util.concurrent.atomic.AtomicLong
-import java.util.HashSet
-import java.util.Random
-import java.util.Date
-
-import scala.collection.mutable.ArrayBuffer
-import scala.collection.mutable.Map
-import scala.collection.mutable.HashMap
+package org.apache.spark.rdd
 
 import org.apache.hadoop.mapred.JobConf
-import org.apache.hadoop.mapred.OutputFormat
-import org.apache.hadoop.mapred.TextOutputFormat
 import org.apache.hadoop.mapred.SequenceFileOutputFormat
-import org.apache.hadoop.mapred.OutputCommitter
-import org.apache.hadoop.mapred.FileOutputCommitter
 import org.apache.hadoop.io.compress.CompressionCodec
 import org.apache.hadoop.io.Writable
-import org.apache.hadoop.io.NullWritable
-import org.apache.hadoop.io.BytesWritable
-import org.apache.hadoop.io.Text
 
 import org.apache.spark.SparkContext._
+import org.apache.spark.Logging
 
 /**
  * Extra functions available on RDDs of (key, value) pairs to create a Hadoop SequenceFile,
  * through an implicit conversion. Note that this can't be part of PairRDDFunctions because
  * we need more implicit parameters to convert our keys and values to Writable.
  *
- * Users should import `spark.SparkContext._` at the top of their program to use these functions.
+ * Import `org.apache.spark.SparkContext._` at the top of their program to use these functions.
  */
 class SequenceFileRDDFunctions[K <% Writable: ClassManifest, V <% Writable : ClassManifest](
     self: RDD[(K, V)])
diff --git a/core/src/main/scala/org/apache/spark/rdd/ShuffledRDD.scala b/core/src/main/scala/org/apache/spark/rdd/ShuffledRDD.scala
index f0e9ab8b80..9537152335 100644
--- a/core/src/main/scala/org/apache/spark/rdd/ShuffledRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/ShuffledRDD.scala
@@ -17,7 +17,7 @@
 
 package org.apache.spark.rdd
 
-import org.apache.spark.{Dependency, Partitioner, RDD, SparkEnv, ShuffleDependency, Partition, TaskContext}
+import org.apache.spark.{Dependency, Partitioner, SparkEnv, ShuffleDependency, Partition, TaskContext}
 
 
 private[spark] class ShuffledRDDPartition(val idx: Int) extends Partition {
diff --git a/core/src/main/scala/org/apache/spark/rdd/SubtractedRDD.scala b/core/src/main/scala/org/apache/spark/rdd/SubtractedRDD.scala
index 7369dfaa74..8c1a29dfff 100644
--- a/core/src/main/scala/org/apache/spark/rdd/SubtractedRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/SubtractedRDD.scala
@@ -20,7 +20,6 @@ package org.apache.spark.rdd
 import java.util.{HashMap => JHashMap}
 import scala.collection.JavaConversions._
 import scala.collection.mutable.ArrayBuffer
-import org.apache.spark.RDD
 import org.apache.spark.Partitioner
 import org.apache.spark.Dependency
 import org.apache.spark.TaskContext
diff --git a/core/src/main/scala/org/apache/spark/rdd/UnionRDD.scala b/core/src/main/scala/org/apache/spark/rdd/UnionRDD.scala
index fd02476b62..ae8a9f36a6 100644
--- a/core/src/main/scala/org/apache/spark/rdd/UnionRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/UnionRDD.scala
@@ -18,7 +18,7 @@
 package org.apache.spark.rdd
 
 import scala.collection.mutable.ArrayBuffer
-import org.apache.spark.{Dependency, RangeDependency, RDD, SparkContext, Partition, TaskContext}
+import org.apache.spark.{Dependency, RangeDependency, SparkContext, Partition, TaskContext}
 import java.io.{ObjectOutputStream, IOException}
 
 private[spark] class UnionPartition[T: ClassManifest](idx: Int, rdd: RDD[T], splitIndex: Int)
diff --git a/core/src/main/scala/org/apache/spark/rdd/ZippedPartitionsRDD.scala b/core/src/main/scala/org/apache/spark/rdd/ZippedPartitionsRDD.scala
index 5ae1db3e67..31e6fd519d 100644
--- a/core/src/main/scala/org/apache/spark/rdd/ZippedPartitionsRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/ZippedPartitionsRDD.scala
@@ -17,7 +17,7 @@
 
 package org.apache.spark.rdd
 
-import org.apache.spark.{Utils, OneToOneDependency, RDD, SparkContext, Partition, TaskContext}
+import org.apache.spark.{OneToOneDependency, SparkContext, Partition, TaskContext}
 import java.io.{ObjectOutputStream, IOException}
 
 private[spark] class ZippedPartitionsPartition(
diff --git a/core/src/main/scala/org/apache/spark/rdd/ZippedRDD.scala b/core/src/main/scala/org/apache/spark/rdd/ZippedRDD.scala
index 3bd00d291b..567b67dfee 100644
--- a/core/src/main/scala/org/apache/spark/rdd/ZippedRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/ZippedRDD.scala
@@ -17,7 +17,7 @@
 
 package org.apache.spark.rdd
 
-import org.apache.spark.{Utils, OneToOneDependency, RDD, SparkContext, Partition, TaskContext}
+import org.apache.spark.{OneToOneDependency, SparkContext, Partition, TaskContext}
 import java.io.{ObjectOutputStream, IOException}
 
 
diff --git a/core/src/main/scala/org/apache/spark/scheduler/DAGScheduler.scala b/core/src/main/scala/org/apache/spark/scheduler/DAGScheduler.scala
index 5ac700bbf4..92add5b073 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/DAGScheduler.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/DAGScheduler.scala
@@ -25,6 +25,7 @@ import java.util.concurrent.atomic.AtomicInteger
 import scala.collection.mutable.{ArrayBuffer, HashMap, HashSet, Map}
 
 import org.apache.spark._
+import org.apache.spark.rdd.RDD
 import org.apache.spark.executor.TaskMetrics
 import org.apache.spark.partial.{ApproximateActionListener, ApproximateEvaluator, PartialResult}
 import org.apache.spark.scheduler.cluster.TaskInfo
diff --git a/core/src/main/scala/org/apache/spark/scheduler/DAGSchedulerEvent.scala b/core/src/main/scala/org/apache/spark/scheduler/DAGSchedulerEvent.scala
index 5b07933eed..0d99670648 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/DAGSchedulerEvent.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/DAGSchedulerEvent.scala
@@ -23,6 +23,7 @@ import org.apache.spark.scheduler.cluster.TaskInfo
 import scala.collection.mutable.Map
 
 import org.apache.spark._
+import org.apache.spark.rdd.RDD
 import org.apache.spark.executor.TaskMetrics
 
 /**
diff --git a/core/src/main/scala/org/apache/spark/scheduler/JobLogger.scala b/core/src/main/scala/org/apache/spark/scheduler/JobLogger.scala
index 98ef4d1e63..c8b78bf00a 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/JobLogger.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/JobLogger.scala
@@ -28,6 +28,7 @@ import scala.collection.mutable.{Map, HashMap, ListBuffer}
 import scala.io.Source

 

 import org.apache.spark._

+import org.apache.spark.rdd.RDD

 import org.apache.spark.executor.TaskMetrics

 import org.apache.spark.scheduler.cluster.TaskInfo

 

diff --git a/core/src/main/scala/org/apache/spark/scheduler/ResultTask.scala b/core/src/main/scala/org/apache/spark/scheduler/ResultTask.scala
index 2f157ccdd2..2b007cbe82 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/ResultTask.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/ResultTask.scala
@@ -17,11 +17,14 @@
 
 package org.apache.spark.scheduler
 
-import org.apache.spark._
 import java.io._
-import util.{MetadataCleaner, TimeStampedHashMap}
 import java.util.zip.{GZIPInputStream, GZIPOutputStream}
 
+import org.apache.spark._
+import org.apache.spark.rdd.RDD
+import org.apache.spark.rdd.RDDCheckpointData
+import org.apache.spark.util.{MetadataCleaner, TimeStampedHashMap}
+
 private[spark] object ResultTask {
 
   // A simple map between the stage id to the serialized byte array of a task.
diff --git a/core/src/main/scala/org/apache/spark/scheduler/ShuffleMapTask.scala b/core/src/main/scala/org/apache/spark/scheduler/ShuffleMapTask.scala
index ca716b44e8..764775fede 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/ShuffleMapTask.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/ShuffleMapTask.scala
@@ -26,6 +26,8 @@ import org.apache.spark._
 import org.apache.spark.executor.ShuffleWriteMetrics
 import org.apache.spark.storage._
 import org.apache.spark.util.{TimeStampedHashMap, MetadataCleaner}
+import org.apache.spark.rdd.RDD
+import org.apache.spark.rdd.RDDCheckpointData
 
 
 private[spark] object ShuffleMapTask {
diff --git a/core/src/main/scala/org/apache/spark/scheduler/SparkListener.scala b/core/src/main/scala/org/apache/spark/scheduler/SparkListener.scala
index 3504424fa9..c3cf4b8907 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/SparkListener.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/SparkListener.scala
@@ -19,8 +19,8 @@ package org.apache.spark.scheduler
 
 import java.util.Properties
 import org.apache.spark.scheduler.cluster.TaskInfo
-import org.apache.spark.util.Distribution
-import org.apache.spark.{Logging, SparkContext, TaskEndReason, Utils}
+import org.apache.spark.util.{Utils, Distribution}
+import org.apache.spark.{Logging, SparkContext, TaskEndReason}
 import org.apache.spark.executor.TaskMetrics
 
 sealed trait SparkListenerEvents
diff --git a/core/src/main/scala/org/apache/spark/scheduler/Stage.scala b/core/src/main/scala/org/apache/spark/scheduler/Stage.scala
index 87b1fe4e0c..aa293dc6b3 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/Stage.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/Stage.scala
@@ -17,9 +17,8 @@
 
 package org.apache.spark.scheduler
 
-import java.net.URI
-
 import org.apache.spark._
+import org.apache.spark.rdd.RDD
 import org.apache.spark.storage.BlockManagerId
 
 /**
diff --git a/core/src/main/scala/org/apache/spark/scheduler/TaskResult.scala b/core/src/main/scala/org/apache/spark/scheduler/TaskResult.scala
index 776675d28c..5c7e5bb977 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/TaskResult.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/TaskResult.scala
@@ -21,8 +21,9 @@ import java.io._
 
 import scala.collection.mutable.Map
 import org.apache.spark.executor.TaskMetrics
-import org.apache.spark.{Utils, SparkEnv}
+import org.apache.spark.{SparkEnv}
 import java.nio.ByteBuffer
+import org.apache.spark.util.Utils
 
 // Task result. Also contains updates to accumulator variables.
 // TODO: Use of distributed cache to return result is a hack to get around
diff --git a/core/src/main/scala/org/apache/spark/scheduler/cluster/ClusterTaskSetManager.scala b/core/src/main/scala/org/apache/spark/scheduler/cluster/ClusterTaskSetManager.scala
index a33307b83a..1b31c8c57e 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/cluster/ClusterTaskSetManager.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/cluster/ClusterTaskSetManager.scala
@@ -26,7 +26,7 @@ import scala.collection.mutable.HashSet
 import scala.math.max
 import scala.math.min
 
-import org.apache.spark.{FetchFailed, Logging, Resubmitted, SparkEnv, Success, TaskEndReason, TaskState, Utils}
+import org.apache.spark.{FetchFailed, Logging, Resubmitted, SparkEnv, Success, TaskEndReason, TaskState}
 import org.apache.spark.{ExceptionFailure, SparkException, TaskResultTooBigFailure}
 import org.apache.spark.TaskState.TaskState
 import org.apache.spark.scheduler._
diff --git a/core/src/main/scala/org/apache/spark/scheduler/cluster/SchedulerBackend.scala b/core/src/main/scala/org/apache/spark/scheduler/cluster/SchedulerBackend.scala
index bde2f73df4..d57eb3276f 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/cluster/SchedulerBackend.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/cluster/SchedulerBackend.scala
@@ -17,7 +17,7 @@
 
 package org.apache.spark.scheduler.cluster
 
-import org.apache.spark.{SparkContext, Utils}
+import org.apache.spark.{SparkContext}
 
 /**
  * A backend interface for cluster scheduling systems that allows plugging in different ones under
diff --git a/core/src/main/scala/org/apache/spark/scheduler/cluster/SparkDeploySchedulerBackend.scala b/core/src/main/scala/org/apache/spark/scheduler/cluster/SparkDeploySchedulerBackend.scala
index ac6dc7d879..d003bf1bba 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/cluster/SparkDeploySchedulerBackend.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/cluster/SparkDeploySchedulerBackend.scala
@@ -17,10 +17,11 @@
 
 package org.apache.spark.scheduler.cluster
 
-import org.apache.spark.{Utils, Logging, SparkContext}
+import org.apache.spark.{Logging, SparkContext}
 import org.apache.spark.deploy.client.{Client, ClientListener}
 import org.apache.spark.deploy.{Command, ApplicationDescription}
 import scala.collection.mutable.HashMap
+import org.apache.spark.util.Utils
 
 private[spark] class SparkDeploySchedulerBackend(
     scheduler: ClusterScheduler,
diff --git a/core/src/main/scala/org/apache/spark/scheduler/cluster/StandaloneClusterMessage.scala b/core/src/main/scala/org/apache/spark/scheduler/cluster/StandaloneClusterMessage.scala
index 1cc5daf673..9c36d221f6 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/cluster/StandaloneClusterMessage.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/cluster/StandaloneClusterMessage.scala
@@ -20,8 +20,7 @@ package org.apache.spark.scheduler.cluster
 import java.nio.ByteBuffer
 
 import org.apache.spark.TaskState.TaskState
-import org.apache.spark.Utils
-import org.apache.spark.util.SerializableBuffer
+import org.apache.spark.util.{Utils, SerializableBuffer}
 
 
 private[spark] sealed trait StandaloneClusterMessage extends Serializable
diff --git a/core/src/main/scala/org/apache/spark/scheduler/cluster/StandaloneSchedulerBackend.scala b/core/src/main/scala/org/apache/spark/scheduler/cluster/StandaloneSchedulerBackend.scala
index 3677a827e0..b4ea0be415 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/cluster/StandaloneSchedulerBackend.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/cluster/StandaloneSchedulerBackend.scala
@@ -28,8 +28,9 @@ import akka.remote.{RemoteClientShutdown, RemoteClientDisconnected, RemoteClient
 import akka.util.Duration
 import akka.util.duration._
 
-import org.apache.spark.{Utils, SparkException, Logging, TaskState}
+import org.apache.spark.{SparkException, Logging, TaskState}
 import org.apache.spark.scheduler.cluster.StandaloneClusterMessages._
+import org.apache.spark.util.Utils
 
 /**
  * A standalone scheduler backend, which waits for standalone executors to connect to it through
diff --git a/core/src/main/scala/org/apache/spark/scheduler/cluster/TaskInfo.scala b/core/src/main/scala/org/apache/spark/scheduler/cluster/TaskInfo.scala
index 7ce14be7fb..9685fb1a67 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/cluster/TaskInfo.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/cluster/TaskInfo.scala
@@ -17,7 +17,7 @@
 
 package org.apache.spark.scheduler.cluster
 
-import org.apache.spark.Utils
+import org.apache.spark.util.Utils
 
 /**
  * Information about a running task attempt inside a TaskSet.
diff --git a/core/src/main/scala/org/apache/spark/scheduler/local/LocalScheduler.scala b/core/src/main/scala/org/apache/spark/scheduler/local/LocalScheduler.scala
index f0ebe66d82..e8fa5e2f17 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/local/LocalScheduler.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/local/LocalScheduler.scala
@@ -34,6 +34,7 @@ import org.apache.spark.scheduler._
 import org.apache.spark.scheduler.cluster._
 import org.apache.spark.scheduler.cluster.SchedulingMode.SchedulingMode
 import akka.actor._
+import org.apache.spark.util.Utils
 
 /**
  * A FIFO or Fair TaskScheduler implementation that runs tasks locally in a thread pool. Optionally
diff --git a/core/src/main/scala/org/apache/spark/scheduler/mesos/CoarseMesosSchedulerBackend.scala b/core/src/main/scala/org/apache/spark/scheduler/mesos/CoarseMesosSchedulerBackend.scala
index f6a2feab28..3dbe61d706 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/mesos/CoarseMesosSchedulerBackend.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/mesos/CoarseMesosSchedulerBackend.scala
@@ -23,7 +23,7 @@ import org.apache.mesos.{Scheduler => MScheduler}
 import org.apache.mesos._
 import org.apache.mesos.Protos.{TaskInfo => MesosTaskInfo, TaskState => MesosTaskState, _}
 
-import org.apache.spark.{SparkException, Utils, Logging, SparkContext}
+import org.apache.spark.{SparkException, Logging, SparkContext}
 import scala.collection.mutable.{ArrayBuffer, HashMap, HashSet}
 import scala.collection.JavaConversions._
 import java.io.File
diff --git a/core/src/main/scala/org/apache/spark/scheduler/mesos/MesosSchedulerBackend.scala b/core/src/main/scala/org/apache/spark/scheduler/mesos/MesosSchedulerBackend.scala
index e002af1742..541f86e338 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/mesos/MesosSchedulerBackend.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/mesos/MesosSchedulerBackend.scala
@@ -23,7 +23,7 @@ import org.apache.mesos.{Scheduler => MScheduler}
 import org.apache.mesos._
 import org.apache.mesos.Protos.{TaskInfo => MesosTaskInfo, TaskState => MesosTaskState, _}
 
-import org.apache.spark.{SparkException, Utils, Logging, SparkContext}
+import org.apache.spark.{SparkException, Logging, SparkContext}
 import scala.collection.mutable.{ArrayBuffer, HashMap, HashSet}
 import scala.collection.JavaConversions._
 import java.io.File
@@ -31,6 +31,7 @@ import org.apache.spark.scheduler.cluster._
 import java.util.{ArrayList => JArrayList, List => JList}
 import java.util.Collections
 import org.apache.spark.TaskState
+import org.apache.spark.util.Utils
 
 /**
  * A SchedulerBackend for running fine-grained tasks on Mesos. Each Spark task is mapped to a
diff --git a/core/src/main/scala/org/apache/spark/JavaSerializer.scala b/core/src/main/scala/org/apache/spark/serializer/JavaSerializer.scala
index f43396cb6b..4de81617b1 100644
--- a/core/src/main/scala/org/apache/spark/JavaSerializer.scala
+++ b/core/src/main/scala/org/apache/spark/serializer/JavaSerializer.scala
@@ -15,12 +15,11 @@
  * limitations under the License.
  */
 
-package org.apache.spark
+package org.apache.spark.serializer
 
 import java.io._
 import java.nio.ByteBuffer
 
-import serializer.{Serializer, SerializerInstance, DeserializationStream, SerializationStream}
 import org.apache.spark.util.ByteBufferInputStream
 
 private[spark] class JavaSerializationStream(out: OutputStream) extends SerializationStream {
diff --git a/core/src/main/scala/org/apache/spark/KryoSerializer.scala b/core/src/main/scala/org/apache/spark/serializer/KryoSerializer.scala
index db86e6db43..24ef204aa1 100644
--- a/core/src/main/scala/org/apache/spark/KryoSerializer.scala
+++ b/core/src/main/scala/org/apache/spark/serializer/KryoSerializer.scala
@@ -15,17 +15,74 @@
  * limitations under the License.
  */
 
-package org.apache.spark
+package org.apache.spark.serializer
 
-import java.io._
 import java.nio.ByteBuffer
-import com.esotericsoftware.kryo.{Kryo, KryoException}
-import com.esotericsoftware.kryo.io.{Input => KryoInput, Output => KryoOutput}
+import java.io.{EOFException, InputStream, OutputStream}
+
 import com.esotericsoftware.kryo.serializers.{JavaSerializer => KryoJavaSerializer}
+import com.esotericsoftware.kryo.{KryoException, Kryo}
+import com.esotericsoftware.kryo.io.{Input => KryoInput, Output => KryoOutput}
 import com.twitter.chill.ScalaKryoInstantiator
-import serializer.{SerializerInstance, DeserializationStream, SerializationStream}
-import org.apache.spark.broadcast._
-import org.apache.spark.storage._
+
+import org.apache.spark.{SerializableWritable, Logging}
+import org.apache.spark.storage.{GetBlock, GotBlock, PutBlock, StorageLevel}
+
+import org.apache.spark.broadcast.HttpBroadcast
+
+/**
+ * A Spark serializer that uses the [[http://code.google.com/p/kryo/wiki/V1Documentation Kryo 1.x library]].
+ */
+class KryoSerializer extends org.apache.spark.serializer.Serializer with Logging {
+  private val bufferSize = System.getProperty("spark.kryoserializer.buffer.mb", "2").toInt * 1024 * 1024
+
+  def newKryoOutput() = new KryoOutput(bufferSize)
+
+  def newKryoInput() = new KryoInput(bufferSize)
+
+  def newKryo(): Kryo = {
+    val instantiator = new ScalaKryoInstantiator
+    val kryo = instantiator.newKryo()
+    val classLoader = Thread.currentThread.getContextClassLoader
+
+    // Register some commonly used classes
+    val toRegister: Seq[AnyRef] = Seq(
+      ByteBuffer.allocate(1),
+      StorageLevel.MEMORY_ONLY,
+      PutBlock("1", ByteBuffer.allocate(1), StorageLevel.MEMORY_ONLY),
+      GotBlock("1", ByteBuffer.allocate(1)),
+      GetBlock("1")
+    )
+
+    for (obj <- toRegister) kryo.register(obj.getClass)
+
+    // Allow sending SerializableWritable
+    kryo.register(classOf[SerializableWritable[_]], new KryoJavaSerializer())
+    kryo.register(classOf[HttpBroadcast[_]], new KryoJavaSerializer())
+
+    // Allow the user to register their own classes by setting spark.kryo.registrator
+    try {
+      Option(System.getProperty("spark.kryo.registrator")).foreach { regCls =>
+        logDebug("Running user registrator: " + regCls)
+        val reg = Class.forName(regCls, true, classLoader).newInstance().asInstanceOf[KryoRegistrator]
+        reg.registerClasses(kryo)
+      }
+    } catch {
+      case _: Exception => println("Failed to register spark.kryo.registrator")
+    }
+
+    kryo.setClassLoader(classLoader)
+
+    // Allow disabling Kryo reference tracking if user knows their object graphs don't have loops
+    kryo.setReferences(System.getProperty("spark.kryo.referenceTracking", "true").toBoolean)
+
+    kryo
+  }
+
+  def newInstance(): SerializerInstance = {
+    new KryoSerializerInstance(this)
+  }
+}
 
 private[spark]
 class KryoSerializationStream(kryo: Kryo, outStream: OutputStream) extends SerializationStream {
@@ -100,57 +157,3 @@ private[spark] class KryoSerializerInstance(ks: KryoSerializer) extends Serializ
 trait KryoRegistrator {
   def registerClasses(kryo: Kryo)
 }
-
-/**
- * A Spark serializer that uses the [[http://code.google.com/p/kryo/wiki/V1Documentation Kryo 1.x library]].
- */
-class KryoSerializer extends org.apache.spark.serializer.Serializer with Logging {
-  private val bufferSize = System.getProperty("spark.kryoserializer.buffer.mb", "2").toInt * 1024 * 1024
-
-  def newKryoOutput() = new KryoOutput(bufferSize)
-
-  def newKryoInput() = new KryoInput(bufferSize)
-
-  def newKryo(): Kryo = {
-    val instantiator = new ScalaKryoInstantiator
-    val kryo = instantiator.newKryo()
-    val classLoader = Thread.currentThread.getContextClassLoader
-
-    // Register some commonly used classes
-    val toRegister: Seq[AnyRef] = Seq(
-      ByteBuffer.allocate(1),
-      StorageLevel.MEMORY_ONLY,
-      PutBlock("1", ByteBuffer.allocate(1), StorageLevel.MEMORY_ONLY),
-      GotBlock("1", ByteBuffer.allocate(1)),
-      GetBlock("1")
-    )
-
-    for (obj <- toRegister) kryo.register(obj.getClass)
-
-    // Allow sending SerializableWritable
-    kryo.register(classOf[SerializableWritable[_]], new KryoJavaSerializer())
-    kryo.register(classOf[HttpBroadcast[_]], new KryoJavaSerializer())
-
-    // Allow the user to register their own classes by setting spark.kryo.registrator
-    try {
-      Option(System.getProperty("spark.kryo.registrator")).foreach { regCls =>
-        logDebug("Running user registrator: " + regCls)
-        val reg = Class.forName(regCls, true, classLoader).newInstance().asInstanceOf[KryoRegistrator]
-        reg.registerClasses(kryo)
-      }
-    } catch {
-      case _: Exception => println("Failed to register spark.kryo.registrator")
-    }
-
-    kryo.setClassLoader(classLoader)
-
-    // Allow disabling Kryo reference tracking if user knows their object graphs don't have loops
-    kryo.setReferences(System.getProperty("spark.kryo.referenceTracking", "true").toBoolean)
-
-    kryo
-  }
-
-  def newInstance(): SerializerInstance = {
-    new KryoSerializerInstance(this)
-  }
-}
diff --git a/core/src/main/scala/org/apache/spark/storage/BlockFetcherIterator.scala b/core/src/main/scala/org/apache/spark/storage/BlockFetcherIterator.scala
index c91f0fc1ad..3aeda3879d 100644
--- a/core/src/main/scala/org/apache/spark/storage/BlockFetcherIterator.scala
+++ b/core/src/main/scala/org/apache/spark/storage/BlockFetcherIterator.scala
@@ -27,12 +27,12 @@ import scala.collection.mutable.Queue
 import io.netty.buffer.ByteBuf
 
 import org.apache.spark.Logging
-import org.apache.spark.Utils
 import org.apache.spark.SparkException
 import org.apache.spark.network.BufferMessage
 import org.apache.spark.network.ConnectionManagerId
 import org.apache.spark.network.netty.ShuffleCopier
 import org.apache.spark.serializer.Serializer
+import org.apache.spark.util.Utils
 
 
 /**
diff --git a/core/src/main/scala/org/apache/spark/storage/BlockManager.scala b/core/src/main/scala/org/apache/spark/storage/BlockManager.scala
index 3299ac98d5..60fdc5f2ee 100644
--- a/core/src/main/scala/org/apache/spark/storage/BlockManager.scala
+++ b/core/src/main/scala/org/apache/spark/storage/BlockManager.scala
@@ -29,11 +29,11 @@ import akka.util.duration._
 
 import it.unimi.dsi.fastutil.io.FastByteArrayOutputStream
 
-import org.apache.spark.{Logging, SparkEnv, SparkException, Utils}
+import org.apache.spark.{Logging, SparkEnv, SparkException}
 import org.apache.spark.io.CompressionCodec
 import org.apache.spark.network._
 import org.apache.spark.serializer.Serializer
-import org.apache.spark.util.{ByteBufferInputStream, IdGenerator, MetadataCleaner, TimeStampedHashMap}
+import org.apache.spark.util._
 
 import sun.nio.ch.DirectBuffer
 
diff --git a/core/src/main/scala/org/apache/spark/storage/BlockManagerId.scala b/core/src/main/scala/org/apache/spark/storage/BlockManagerId.scala
index a22a80decc..74207f59af 100644
--- a/core/src/main/scala/org/apache/spark/storage/BlockManagerId.scala
+++ b/core/src/main/scala/org/apache/spark/storage/BlockManagerId.scala
@@ -19,7 +19,7 @@ package org.apache.spark.storage
 
 import java.io.{Externalizable, IOException, ObjectInput, ObjectOutput}
 import java.util.concurrent.ConcurrentHashMap
-import org.apache.spark.Utils
+import org.apache.spark.util.Utils
 
 /**
  * This class represent an unique identifier for a BlockManager.
diff --git a/core/src/main/scala/org/apache/spark/storage/BlockManagerMasterActor.scala b/core/src/main/scala/org/apache/spark/storage/BlockManagerMasterActor.scala
index baa4a1da50..c7b23ab094 100644
--- a/core/src/main/scala/org/apache/spark/storage/BlockManagerMasterActor.scala
+++ b/core/src/main/scala/org/apache/spark/storage/BlockManagerMasterActor.scala
@@ -28,8 +28,9 @@ import akka.pattern.ask
 import akka.util.Duration
 import akka.util.duration._
 
-import org.apache.spark.{Logging, Utils, SparkException}
+import org.apache.spark.{Logging, SparkException}
 import org.apache.spark.storage.BlockManagerMessages._
+import org.apache.spark.util.Utils
 
 
 /**
diff --git a/core/src/main/scala/org/apache/spark/storage/BlockManagerWorker.scala b/core/src/main/scala/org/apache/spark/storage/BlockManagerWorker.scala
index f4856020e5..678c38203c 100644
--- a/core/src/main/scala/org/apache/spark/storage/BlockManagerWorker.scala
+++ b/core/src/main/scala/org/apache/spark/storage/BlockManagerWorker.scala
@@ -19,8 +19,9 @@ package org.apache.spark.storage
 
 import java.nio.ByteBuffer
 
-import org.apache.spark.{Logging, Utils}
+import org.apache.spark.{Logging}
 import org.apache.spark.network._
+import org.apache.spark.util.Utils
 
 /**
  * A network interface for BlockManager. Each slave should have one
diff --git a/core/src/main/scala/org/apache/spark/storage/DiskStore.scala b/core/src/main/scala/org/apache/spark/storage/DiskStore.scala
index fd945e065c..fc25ef0fae 100644
--- a/core/src/main/scala/org/apache/spark/storage/DiskStore.scala
+++ b/core/src/main/scala/org/apache/spark/storage/DiskStore.scala
@@ -28,12 +28,12 @@ import scala.collection.mutable.ArrayBuffer
 
 import it.unimi.dsi.fastutil.io.FastBufferedOutputStream
 
-import org.apache.spark.Utils
 import org.apache.spark.executor.ExecutorExitCode
 import org.apache.spark.serializer.{Serializer, SerializationStream}
 import org.apache.spark.Logging
 import org.apache.spark.network.netty.ShuffleSender
 import org.apache.spark.network.netty.PathResolver
+import org.apache.spark.util.Utils
 
 
 /**
diff --git a/core/src/main/scala/org/apache/spark/storage/MemoryStore.scala b/core/src/main/scala/org/apache/spark/storage/MemoryStore.scala
index 828dc0f22d..3b3b2342fa 100644
--- a/core/src/main/scala/org/apache/spark/storage/MemoryStore.scala
+++ b/core/src/main/scala/org/apache/spark/storage/MemoryStore.scala
@@ -19,9 +19,9 @@ package org.apache.spark.storage
 
 import java.util.LinkedHashMap
 import java.util.concurrent.ArrayBlockingQueue
-import org.apache.spark.{SizeEstimator, Utils}
 import java.nio.ByteBuffer
 import collection.mutable.ArrayBuffer
+import org.apache.spark.util.{SizeEstimator, Utils}
 
 /**
  * Stores blocks in memory, either as ArrayBuffers of deserialized Java objects or as
diff --git a/core/src/main/scala/org/apache/spark/storage/StorageUtils.scala b/core/src/main/scala/org/apache/spark/storage/StorageUtils.scala
index 0bba1dac54..2bb7715696 100644
--- a/core/src/main/scala/org/apache/spark/storage/StorageUtils.scala
+++ b/core/src/main/scala/org/apache/spark/storage/StorageUtils.scala
@@ -17,8 +17,9 @@
 
 package org.apache.spark.storage
 
-import org.apache.spark.{Utils, SparkContext}
+import org.apache.spark.{SparkContext}
 import BlockManagerMasterActor.BlockStatus
+import org.apache.spark.util.Utils
 
 private[spark]
 case class StorageStatus(blockManagerId: BlockManagerId, maxMem: Long,
diff --git a/core/src/main/scala/org/apache/spark/storage/ThreadingTest.scala b/core/src/main/scala/org/apache/spark/storage/ThreadingTest.scala
index 1d5afe9b08..f2ae8dd97d 100644
--- a/core/src/main/scala/org/apache/spark/storage/ThreadingTest.scala
+++ b/core/src/main/scala/org/apache/spark/storage/ThreadingTest.scala
@@ -19,9 +19,9 @@ package org.apache.spark.storage
 
 import akka.actor._
 
-import org.apache.spark.KryoSerializer
 import java.util.concurrent.ArrayBlockingQueue
 import util.Random
+import org.apache.spark.serializer.KryoSerializer
 
 /**
  * This class tests the BlockManager and MemoryStore for thread safety and
diff --git a/core/src/main/scala/org/apache/spark/ui/SparkUI.scala b/core/src/main/scala/org/apache/spark/ui/SparkUI.scala
index 4688effe0a..ad456ea565 100644
--- a/core/src/main/scala/org/apache/spark/ui/SparkUI.scala
+++ b/core/src/main/scala/org/apache/spark/ui/SparkUI.scala
@@ -21,12 +21,13 @@ import javax.servlet.http.HttpServletRequest
 
 import org.eclipse.jetty.server.{Handler, Server}
 
-import org.apache.spark.{Logging, SparkContext, SparkEnv, Utils}
+import org.apache.spark.{Logging, SparkContext, SparkEnv}
 import org.apache.spark.ui.env.EnvironmentUI
 import org.apache.spark.ui.exec.ExecutorsUI
 import org.apache.spark.ui.storage.BlockManagerUI
 import org.apache.spark.ui.jobs.JobProgressUI
 import org.apache.spark.ui.JettyUtils._
+import org.apache.spark.util.Utils
 
 /** Top level user interface for Spark */
 private[spark] class SparkUI(sc: SparkContext) extends Logging {
diff --git a/core/src/main/scala/org/apache/spark/ui/exec/ExecutorsUI.scala b/core/src/main/scala/org/apache/spark/ui/exec/ExecutorsUI.scala
index efe6b474e0..6e56c22d04 100644
--- a/core/src/main/scala/org/apache/spark/ui/exec/ExecutorsUI.scala
+++ b/core/src/main/scala/org/apache/spark/ui/exec/ExecutorsUI.scala
@@ -7,13 +7,14 @@ import scala.xml.Node
 
 import org.eclipse.jetty.server.Handler
 
-import org.apache.spark.{ExceptionFailure, Logging, Utils, SparkContext}
+import org.apache.spark.{ExceptionFailure, Logging, SparkContext}
 import org.apache.spark.executor.TaskMetrics
 import org.apache.spark.scheduler.cluster.TaskInfo
 import org.apache.spark.scheduler.{SparkListenerTaskStart, SparkListenerTaskEnd, SparkListener}
 import org.apache.spark.ui.JettyUtils._
 import org.apache.spark.ui.Page.Executors
 import org.apache.spark.ui.UIUtils
+import org.apache.spark.util.Utils
 
 
 private[spark] class ExecutorsUI(val sc: SparkContext) {
diff --git a/core/src/main/scala/org/apache/spark/ui/jobs/JobProgressListener.scala b/core/src/main/scala/org/apache/spark/ui/jobs/JobProgressListener.scala
index ae02226300..86e0af0399 100644
--- a/core/src/main/scala/org/apache/spark/ui/jobs/JobProgressListener.scala
+++ b/core/src/main/scala/org/apache/spark/ui/jobs/JobProgressListener.scala
@@ -3,7 +3,7 @@ package org.apache.spark.ui.jobs
 import scala.Seq
 import scala.collection.mutable.{ListBuffer, HashMap, HashSet}
 
-import org.apache.spark.{ExceptionFailure, SparkContext, Success, Utils}
+import org.apache.spark.{ExceptionFailure, SparkContext, Success}
 import org.apache.spark.scheduler._
 import org.apache.spark.scheduler.cluster.TaskInfo
 import org.apache.spark.executor.TaskMetrics
diff --git a/core/src/main/scala/org/apache/spark/ui/jobs/JobProgressUI.scala b/core/src/main/scala/org/apache/spark/ui/jobs/JobProgressUI.scala
index 1bb7638bd9..6aecef5120 100644
--- a/core/src/main/scala/org/apache/spark/ui/jobs/JobProgressUI.scala
+++ b/core/src/main/scala/org/apache/spark/ui/jobs/JobProgressUI.scala
@@ -29,11 +29,12 @@ import scala.Seq
 import scala.collection.mutable.{HashSet, ListBuffer, HashMap, ArrayBuffer}
 
 import org.apache.spark.ui.JettyUtils._
-import org.apache.spark.{ExceptionFailure, SparkContext, Success, Utils}
+import org.apache.spark.{ExceptionFailure, SparkContext, Success}
 import org.apache.spark.scheduler._
 import collection.mutable
 import org.apache.spark.scheduler.cluster.SchedulingMode
 import org.apache.spark.scheduler.cluster.SchedulingMode.SchedulingMode
+import org.apache.spark.util.Utils
 
 /** Web UI showing progress status of all jobs in the given SparkContext. */
 private[spark] class JobProgressUI(val sc: SparkContext) {
diff --git a/core/src/main/scala/org/apache/spark/ui/jobs/StagePage.scala b/core/src/main/scala/org/apache/spark/ui/jobs/StagePage.scala
index 2fe85bc0cf..a9969ab1c0 100644
--- a/core/src/main/scala/org/apache/spark/ui/jobs/StagePage.scala
+++ b/core/src/main/scala/org/apache/spark/ui/jobs/StagePage.scala
@@ -25,8 +25,8 @@ import scala.xml.Node
 
 import org.apache.spark.ui.UIUtils._
 import org.apache.spark.ui.Page._
-import org.apache.spark.util.Distribution
-import org.apache.spark.{ExceptionFailure, Utils}
+import org.apache.spark.util.{Utils, Distribution}
+import org.apache.spark.{ExceptionFailure}
 import org.apache.spark.scheduler.cluster.TaskInfo
 import org.apache.spark.executor.TaskMetrics
 
diff --git a/core/src/main/scala/org/apache/spark/ui/jobs/StageTable.scala b/core/src/main/scala/org/apache/spark/ui/jobs/StageTable.scala
index beb0574548..71e58a977e 100644
--- a/core/src/main/scala/org/apache/spark/ui/jobs/StageTable.scala
+++ b/core/src/main/scala/org/apache/spark/ui/jobs/StageTable.scala
@@ -5,9 +5,9 @@ import java.util.Date
 import scala.xml.Node
 import scala.collection.mutable.HashSet
 
-import org.apache.spark.Utils
 import org.apache.spark.scheduler.cluster.{SchedulingMode, TaskInfo}
 import org.apache.spark.scheduler.Stage
+import org.apache.spark.util.Utils
 
 
 /** Page showing list of all ongoing and recently finished stages */
diff --git a/core/src/main/scala/org/apache/spark/ui/storage/IndexPage.scala b/core/src/main/scala/org/apache/spark/ui/storage/IndexPage.scala
index 1eb4a7a85e..c3ec907370 100644
--- a/core/src/main/scala/org/apache/spark/ui/storage/IndexPage.scala
+++ b/core/src/main/scala/org/apache/spark/ui/storage/IndexPage.scala
@@ -22,9 +22,9 @@ import javax.servlet.http.HttpServletRequest
 import scala.xml.Node
 
 import org.apache.spark.storage.{RDDInfo, StorageUtils}
-import org.apache.spark.Utils
 import org.apache.spark.ui.UIUtils._
 import org.apache.spark.ui.Page._
+import org.apache.spark.util.Utils
 
 /** Page showing list of RDD's currently stored in the cluster */
 private[spark] class IndexPage(parent: BlockManagerUI) {
diff --git a/core/src/main/scala/org/apache/spark/ui/storage/RDDPage.scala b/core/src/main/scala/org/apache/spark/ui/storage/RDDPage.scala
index 37baf17f7a..43c1257677 100644
--- a/core/src/main/scala/org/apache/spark/ui/storage/RDDPage.scala
+++ b/core/src/main/scala/org/apache/spark/ui/storage/RDDPage.scala
@@ -21,11 +21,11 @@ import javax.servlet.http.HttpServletRequest
 
 import scala.xml.Node
 
-import org.apache.spark.Utils
 import org.apache.spark.storage.{StorageStatus, StorageUtils}
 import org.apache.spark.storage.BlockManagerMasterActor.BlockStatus
 import org.apache.spark.ui.UIUtils._
 import org.apache.spark.ui.Page._
+import org.apache.spark.util.Utils
 
 
 /** Page showing storage details for a given RDD */
diff --git a/core/src/main/scala/org/apache/spark/ClosureCleaner.scala b/core/src/main/scala/org/apache/spark/util/ClosureCleaner.scala
index 71d9e62d4f..7108595e3e 100644
--- a/core/src/main/scala/org/apache/spark/ClosureCleaner.scala
+++ b/core/src/main/scala/org/apache/spark/util/ClosureCleaner.scala
@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark
+package org.apache.spark.util
 
 import java.lang.reflect.Field
 
@@ -25,6 +25,7 @@ import scala.collection.mutable.Set
 import org.objectweb.asm.{ClassReader, ClassVisitor, MethodVisitor, Type}
 import org.objectweb.asm.Opcodes._
 import java.io.{InputStream, IOException, ByteArrayOutputStream, ByteArrayInputStream, BufferedInputStream}
+import org.apache.spark.Logging
 
 private[spark] object ClosureCleaner extends Logging {
   // Get an ASM class reader for a given class from the JAR that loaded it
diff --git a/core/src/main/scala/org/apache/spark/util/MemoryParam.scala b/core/src/main/scala/org/apache/spark/util/MemoryParam.scala
index 0ee6707826..4869c9897a 100644
--- a/core/src/main/scala/org/apache/spark/util/MemoryParam.scala
+++ b/core/src/main/scala/org/apache/spark/util/MemoryParam.scala
@@ -17,8 +17,6 @@
 
 package org.apache.spark.util
 
-import org.apache.spark.Utils
-
 /**
  * An extractor object for parsing JVM memory strings, such as "10g", into an Int representing
  * the number of megabytes. Supports the same formats as Utils.memoryStringToMb.
diff --git a/core/src/main/scala/org/apache/spark/SizeEstimator.scala b/core/src/main/scala/org/apache/spark/util/SizeEstimator.scala
index 4bfc837710..a25b37a2a9 100644
--- a/core/src/main/scala/org/apache/spark/SizeEstimator.scala
+++ b/core/src/main/scala/org/apache/spark/util/SizeEstimator.scala
@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark
+package org.apache.spark.util
 
 import java.lang.reflect.Field
 import java.lang.reflect.Modifier
@@ -30,6 +30,7 @@ import java.lang.management.ManagementFactory
 import scala.collection.mutable.ArrayBuffer
 
 import it.unimi.dsi.fastutil.ints.IntOpenHashSet
+import org.apache.spark.Logging
 
 /**
  * Estimates the sizes of Java objects (number of bytes of memory they occupy), for use in 
diff --git a/core/src/main/scala/org/apache/spark/Utils.scala b/core/src/main/scala/org/apache/spark/util/Utils.scala
index 1e17deb010..bb47fc0a2c 100644
--- a/core/src/main/scala/org/apache/spark/Utils.scala
+++ b/core/src/main/scala/org/apache/spark/util/Utils.scala
@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark
+package org.apache.spark.util
 
 import java.io._
 import java.net.{InetAddress, URL, URI, NetworkInterface, Inet4Address, ServerSocket}
@@ -36,12 +36,13 @@ import org.apache.hadoop.fs.{Path, FileSystem, FileUtil}
 import org.apache.spark.serializer.{DeserializationStream, SerializationStream, SerializerInstance}
 import org.apache.spark.deploy.SparkHadoopUtil
 import java.nio.ByteBuffer
+import org.apache.spark.{SparkEnv, SparkException, Logging}
 
 
 /**
  * Various utility methods used by Spark.
  */
-private object Utils extends Logging {
+private[spark] object Utils extends Logging {
 
   /** Serialize an object using Java serialization */
   def serialize[T](o: T): Array[Byte] = {
diff --git a/core/src/test/scala/org/apache/spark/CheckpointSuite.scala b/core/src/test/scala/org/apache/spark/CheckpointSuite.scala
index 23b14f4245..d9103aebb7 100644
--- a/core/src/test/scala/org/apache/spark/CheckpointSuite.scala
+++ b/core/src/test/scala/org/apache/spark/CheckpointSuite.scala
@@ -22,6 +22,7 @@ import java.io.File
 import org.apache.spark.rdd._
 import org.apache.spark.SparkContext._
 import storage.StorageLevel
+import org.apache.spark.util.Utils
 
 class CheckpointSuite extends FunSuite with LocalSparkContext with Logging {
   initLogging()
diff --git a/core/src/test/scala/org/apache/spark/DriverSuite.scala b/core/src/test/scala/org/apache/spark/DriverSuite.scala
index b08aad1a6f..01a72d8401 100644
--- a/core/src/test/scala/org/apache/spark/DriverSuite.scala
+++ b/core/src/test/scala/org/apache/spark/DriverSuite.scala
@@ -26,6 +26,7 @@ import org.scalatest.FunSuite
 import org.scalatest.concurrent.Timeouts
 import org.scalatest.prop.TableDrivenPropertyChecks._
 import org.scalatest.time.SpanSugar._
+import org.apache.spark.util.Utils
 
 class DriverSuite extends FunSuite with Timeouts {
   test("driver should exit after finishing") {
diff --git a/core/src/test/scala/org/apache/spark/FailureSuite.scala b/core/src/test/scala/org/apache/spark/FailureSuite.scala
index ee89a7a387..af448fcb37 100644
--- a/core/src/test/scala/org/apache/spark/FailureSuite.scala
+++ b/core/src/test/scala/org/apache/spark/FailureSuite.scala
@@ -20,6 +20,7 @@ package org.apache.spark
 import org.scalatest.FunSuite
 
 import SparkContext._
+import org.apache.spark.util.NonSerializable
 
 // Common state shared by FailureSuite-launched tasks. We use a global object
 // for this because any local variables used in the task closures will rightfully
diff --git a/core/src/test/scala/org/apache/spark/PartitionPruningRDDSuite.scala b/core/src/test/scala/org/apache/spark/PartitionPruningRDDSuite.scala
index adbe805916..5a18dd13ff 100644
--- a/core/src/test/scala/org/apache/spark/PartitionPruningRDDSuite.scala
+++ b/core/src/test/scala/org/apache/spark/PartitionPruningRDDSuite.scala
@@ -2,7 +2,7 @@ package org.apache.spark
 
 import org.scalatest.FunSuite
 import org.apache.spark.SparkContext._
-import org.apache.spark.rdd.PartitionPruningRDD
+import org.apache.spark.rdd.{RDD, PartitionPruningRDD}
 
 
 class PartitionPruningRDDSuite extends FunSuite with SharedSparkContext {
diff --git a/core/src/test/scala/org/apache/spark/PartitioningSuite.scala b/core/src/test/scala/org/apache/spark/PartitioningSuite.scala
index 7669cf6fb1..7d938917f2 100644
--- a/core/src/test/scala/org/apache/spark/PartitioningSuite.scala
+++ b/core/src/test/scala/org/apache/spark/PartitioningSuite.scala
@@ -17,11 +17,14 @@
 
 package org.apache.spark
 
-import org.scalatest.FunSuite
+import scala.math.abs
 import scala.collection.mutable.ArrayBuffer
-import SparkContext._
+
+import org.scalatest.FunSuite
+
+import org.apache.spark.SparkContext._
 import org.apache.spark.util.StatCounter
-import scala.math.abs
+import org.apache.spark.rdd.RDD
 
 class PartitioningSuite extends FunSuite with SharedSparkContext {
 
diff --git a/core/src/test/scala/org/apache/spark/ShuffleSuite.scala b/core/src/test/scala/org/apache/spark/ShuffleSuite.scala
index 357175e89e..db717865db 100644
--- a/core/src/test/scala/org/apache/spark/ShuffleSuite.scala
+++ b/core/src/test/scala/org/apache/spark/ShuffleSuite.scala
@@ -22,8 +22,9 @@ import org.scalatest.matchers.ShouldMatchers
 
 import org.apache.spark.SparkContext._
 import org.apache.spark.ShuffleSuite.NonJavaSerializableClass
-import org.apache.spark.rdd.{SubtractedRDD, CoGroupedRDD, OrderedRDDFunctions, ShuffledRDD}
+import org.apache.spark.rdd.{RDD, SubtractedRDD, CoGroupedRDD, OrderedRDDFunctions, ShuffledRDD}
 import org.apache.spark.util.MutablePair
+import org.apache.spark.serializer.KryoSerializer
 
 
 class ShuffleSuite extends FunSuite with ShouldMatchers with LocalSparkContext {
diff --git a/core/src/test/scala/org/apache/spark/PairRDDFunctionsSuite.scala b/core/src/test/scala/org/apache/spark/rdd/PairRDDFunctionsSuite.scala
index f79752b34e..31f97fc139 100644
--- a/core/src/test/scala/org/apache/spark/PairRDDFunctionsSuite.scala
+++ b/core/src/test/scala/org/apache/spark/rdd/PairRDDFunctionsSuite.scala
@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark
+package org.apache.spark.rdd
 
 import scala.collection.mutable.ArrayBuffer
 import scala.collection.mutable.HashSet
@@ -24,6 +24,7 @@ import org.scalatest.FunSuite
 
 import com.google.common.io.Files
 import org.apache.spark.SparkContext._
+import org.apache.spark.{Partitioner, SharedSparkContext}
 
 
 class PairRDDFunctionsSuite extends FunSuite with SharedSparkContext {
diff --git a/core/src/test/scala/org/apache/spark/RDDSuite.scala b/core/src/test/scala/org/apache/spark/rdd/RDDSuite.scala
index 342ba8adb2..adc971050e 100644
--- a/core/src/test/scala/org/apache/spark/RDDSuite.scala
+++ b/core/src/test/scala/org/apache/spark/rdd/RDDSuite.scala
@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark
+package org.apache.spark.rdd
 
 import scala.collection.mutable.HashMap
 import org.scalatest.FunSuite
@@ -24,6 +24,8 @@ import org.scalatest.time.{Span, Millis}
 import org.apache.spark.SparkContext._
 import org.apache.spark.rdd._
 import scala.collection.parallel.mutable
+import org.apache.spark._
+import org.apache.spark.rdd.CoalescedRDDPartition
 
 class RDDSuite extends FunSuite with SharedSparkContext {
 
diff --git a/core/src/test/scala/org/apache/spark/SortingSuite.scala b/core/src/test/scala/org/apache/spark/rdd/SortingSuite.scala
index f4fa9511dd..2f7bd370fc 100644
--- a/core/src/test/scala/org/apache/spark/SortingSuite.scala
+++ b/core/src/test/scala/org/apache/spark/rdd/SortingSuite.scala
@@ -15,12 +15,14 @@
  * limitations under the License.
  */
 
-package org.apache.spark
+package org.apache.spark.rdd
 
 import org.scalatest.FunSuite
 import org.scalatest.BeforeAndAfter
 import org.scalatest.matchers.ShouldMatchers
-import SparkContext._
+
+import org.apache.spark.{Logging, SharedSparkContext}
+import org.apache.spark.SparkContext._
 
 class SortingSuite extends FunSuite with SharedSparkContext with ShouldMatchers with Logging {
 
diff --git a/core/src/test/scala/org/apache/spark/scheduler/DAGSchedulerSuite.scala b/core/src/test/scala/org/apache/spark/scheduler/DAGSchedulerSuite.scala
index 94df282b28..94f66c94c6 100644
--- a/core/src/test/scala/org/apache/spark/scheduler/DAGSchedulerSuite.scala
+++ b/core/src/test/scala/org/apache/spark/scheduler/DAGSchedulerSuite.scala
@@ -24,7 +24,7 @@ import org.scalatest.BeforeAndAfter
 
 import org.apache.spark.LocalSparkContext
 import org.apache.spark.MapOutputTracker
-import org.apache.spark.RDD
+import org.apache.spark.rdd.RDD
 import org.apache.spark.SparkContext
 import org.apache.spark.Partition
 import org.apache.spark.TaskContext
diff --git a/core/src/test/scala/org/apache/spark/scheduler/JobLoggerSuite.scala b/core/src/test/scala/org/apache/spark/scheduler/JobLoggerSuite.scala
index f5b3e97222..cece60dda7 100644
--- a/core/src/test/scala/org/apache/spark/scheduler/JobLoggerSuite.scala
+++ b/core/src/test/scala/org/apache/spark/scheduler/JobLoggerSuite.scala
@@ -19,11 +19,15 @@ package org.apache.spark.scheduler
 
 import java.util.Properties
 import java.util.concurrent.LinkedBlockingQueue
+
+import scala.collection.mutable
+
 import org.scalatest.FunSuite
 import org.scalatest.matchers.ShouldMatchers
-import scala.collection.mutable
+
 import org.apache.spark._
 import org.apache.spark.SparkContext._
+import org.apache.spark.rdd.RDD
 
 
 class JobLoggerSuite extends FunSuite with LocalSparkContext with ShouldMatchers {
diff --git a/core/src/test/scala/org/apache/spark/scheduler/TaskContextSuite.scala b/core/src/test/scala/org/apache/spark/scheduler/TaskContextSuite.scala
index 0347cc02d7..e31a116a75 100644
--- a/core/src/test/scala/org/apache/spark/scheduler/TaskContextSuite.scala
+++ b/core/src/test/scala/org/apache/spark/scheduler/TaskContextSuite.scala
@@ -20,7 +20,7 @@ package org.apache.spark.scheduler
 import org.scalatest.FunSuite
 import org.scalatest.BeforeAndAfter
 import org.apache.spark.TaskContext
-import org.apache.spark.RDD
+import org.apache.spark.rdd.RDD
 import org.apache.spark.SparkContext
 import org.apache.spark.Partition
 import org.apache.spark.LocalSparkContext
diff --git a/core/src/test/scala/org/apache/spark/scheduler/cluster/ClusterTaskSetManagerSuite.scala b/core/src/test/scala/org/apache/spark/scheduler/cluster/ClusterTaskSetManagerSuite.scala
index a4f63baf3d..ff70a2cdf0 100644
--- a/core/src/test/scala/org/apache/spark/scheduler/cluster/ClusterTaskSetManagerSuite.scala
+++ b/core/src/test/scala/org/apache/spark/scheduler/cluster/ClusterTaskSetManagerSuite.scala
@@ -26,7 +26,7 @@ import org.apache.spark._
 import org.apache.spark.scheduler._
 import org.apache.spark.executor.TaskMetrics
 import java.nio.ByteBuffer
-import org.apache.spark.util.FakeClock
+import org.apache.spark.util.{Utils, FakeClock}
 
 /**
  * A mock ClusterScheduler implementation that just remembers information about tasks started and
diff --git a/core/src/test/scala/org/apache/spark/KryoSerializerSuite.scala b/core/src/test/scala/org/apache/spark/serializer/KryoSerializerSuite.scala
index d7b23c93fe..0164dda0ba 100644
--- a/core/src/test/scala/org/apache/spark/KryoSerializerSuite.scala
+++ b/core/src/test/scala/org/apache/spark/serializer/KryoSerializerSuite.scala
@@ -15,14 +15,15 @@
  * limitations under the License.
  */
 
-package org.apache.spark
+package org.apache.spark.serializer
 
 import scala.collection.mutable
 
-import org.scalatest.FunSuite
-import com.esotericsoftware.kryo._
+import com.esotericsoftware.kryo.Kryo
 
-import KryoTest._
+import org.scalatest.FunSuite
+import org.apache.spark.SharedSparkContext
+import org.apache.spark.serializer.KryoTest._
 
 class KryoSerializerSuite extends FunSuite with SharedSparkContext {
   test("basic types") {
@@ -103,7 +104,6 @@ class KryoSerializerSuite extends FunSuite with SharedSparkContext {
   }
 
   test("custom registrator") {
-    import KryoTest._
     System.setProperty("spark.kryo.registrator", classOf[MyRegistrator].getName)
 
     val ser = (new KryoSerializer).newInstance()
@@ -167,7 +167,7 @@ class KryoSerializerSuite extends FunSuite with SharedSparkContext {
   }
 
   override def beforeAll() {
-    System.setProperty("spark.serializer", "org.apache.spark.KryoSerializer")
+    System.setProperty("spark.serializer", "org.apache.spark.serializer.KryoSerializer")
     System.setProperty("spark.kryo.registrator", classOf[MyRegistrator].getName)
     super.beforeAll()
   }
diff --git a/core/src/test/scala/org/apache/spark/storage/BlockManagerSuite.scala b/core/src/test/scala/org/apache/spark/storage/BlockManagerSuite.scala
index 88ba10f2f2..038a9acb85 100644
--- a/core/src/test/scala/org/apache/spark/storage/BlockManagerSuite.scala
+++ b/core/src/test/scala/org/apache/spark/storage/BlockManagerSuite.scala
@@ -29,12 +29,8 @@ import org.scalatest.concurrent.Timeouts._
 import org.scalatest.matchers.ShouldMatchers._
 import org.scalatest.time.SpanSugar._
 
-import org.apache.spark.JavaSerializer
-import org.apache.spark.KryoSerializer
-import org.apache.spark.SizeEstimator
-import org.apache.spark.Utils
-import org.apache.spark.util.AkkaUtils
-import org.apache.spark.util.ByteBufferInputStream
+import org.apache.spark.util.{SizeEstimator, Utils, AkkaUtils, ByteBufferInputStream}
+import org.apache.spark.serializer.{JavaSerializer, KryoSerializer}
 
 
 class BlockManagerSuite extends FunSuite with BeforeAndAfter with PrivateMethodTester {
diff --git a/core/src/test/scala/org/apache/spark/ClosureCleanerSuite.scala b/core/src/test/scala/org/apache/spark/util/ClosureCleanerSuite.scala
index 8494899b98..0ed366fb70 100644
--- a/core/src/test/scala/org/apache/spark/ClosureCleanerSuite.scala
+++ b/core/src/test/scala/org/apache/spark/util/ClosureCleanerSuite.scala
@@ -15,13 +15,14 @@
  * limitations under the License.
  */
 
-package org.apache.spark
+package org.apache.spark.util
 
 import java.io.NotSerializableException
 
 import org.scalatest.FunSuite
+
+import org.apache.spark.SparkContext
 import org.apache.spark.LocalSparkContext._
-import SparkContext._
 
 class ClosureCleanerSuite extends FunSuite {
   test("closures inside an object") {
diff --git a/core/src/test/scala/org/apache/spark/SizeEstimatorSuite.scala b/core/src/test/scala/org/apache/spark/util/SizeEstimatorSuite.scala
index 214ac74898..4e40dcbdee 100644
--- a/core/src/test/scala/org/apache/spark/SizeEstimatorSuite.scala
+++ b/core/src/test/scala/org/apache/spark/util/SizeEstimatorSuite.scala
@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark
+package org.apache.spark.util
 
 import org.scalatest.FunSuite
 import org.scalatest.BeforeAndAfterAll
diff --git a/core/src/test/scala/org/apache/spark/UtilsSuite.scala b/core/src/test/scala/org/apache/spark/util/UtilsSuite.scala
index 3a908720a8..e2859caf58 100644
--- a/core/src/test/scala/org/apache/spark/UtilsSuite.scala
+++ b/core/src/test/scala/org/apache/spark/util/UtilsSuite.scala
@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.spark
+package org.apache.spark.util
 
 import com.google.common.base.Charsets
 import com.google.common.io.Files