diff --git a/core/src/main/scala/org/apache/spark/SparkContext.scala b/core/src/main/scala/org/apache/spark/SparkContext.scala
index d7e681d921bd439dbc4a71ef5665fdc8a874b1a9..9a3d36b51e4dfa8f334b0cc64b359ae2c9e25d0a 100644
--- a/core/src/main/scala/org/apache/spark/SparkContext.scala
+++ b/core/src/main/scala/org/apache/spark/SparkContext.scala
@@ -345,9 +345,20 @@ class SparkContext(
   }
 
   /**
-   * Get an RDD for a Hadoop-readable dataset from a Hadoop JobConf given its InputFormat and any
-   * other necessary info (e.g. file name for a filesystem-based dataset, table name for HyperTable,
-   * etc).
+   * Get an RDD for a Hadoop-readable dataset from a Hadoop JobConf given its InputFormat and other
+   * necessary info (e.g. file name for a filesystem-based dataset, table name for HyperTable),
+   * using the older MapReduce API (`org.apache.hadoop.mapred`).
+   *
+   * @param conf JobConf for setting up the dataset
+   * @param inputFormatClass Class of the [[InputFormat]]
+   * @param keyClass Class of the keys
+   * @param valueClass Class of the values
+   * @param minSplits Minimum number of Hadoop Splits to generate.
+   * @param cloneRecords If true, Spark will clone the records produced by Hadoop RecordReader.
+   *                     Most RecordReader implementations reuse wrapper objects across multiple
+   *                     records, and can cause problems in RDD collect or aggregation operations.
+   *                     By default the records are cloned in Spark. However, application
+   *                     programmers can explicitly disable the cloning for better performance.
    */
   def hadoopRDD[K: ClassTag, V: ClassTag](
       conf: JobConf,
@@ -355,11 +366,11 @@ class SparkContext(
       keyClass: Class[K],
       valueClass: Class[V],
       minSplits: Int = defaultMinSplits,
-      cloneKeyValues: Boolean = true
+      cloneRecords: Boolean = true
       ): RDD[(K, V)] = {
     // Add necessary security credentials to the JobConf before broadcasting it.
     SparkHadoopUtil.get.addCredentials(conf)
-    new HadoopRDD(this, conf, inputFormatClass, keyClass, valueClass, minSplits, cloneKeyValues)
+    new HadoopRDD(this, conf, inputFormatClass, keyClass, valueClass, minSplits, cloneRecords)
   }
 
   /** Get an RDD for a Hadoop file with an arbitrary InputFormat */
@@ -369,7 +380,7 @@ class SparkContext(
       keyClass: Class[K],
       valueClass: Class[V],
       minSplits: Int = defaultMinSplits,
-      cloneKeyValues: Boolean = true
+      cloneRecords: Boolean = true
       ): RDD[(K, V)] = {
     // A Hadoop configuration can be about 10 KB, which is pretty big, so broadcast it.
     val confBroadcast = broadcast(new SerializableWritable(hadoopConfiguration))
@@ -382,7 +393,7 @@ class SparkContext(
       keyClass,
       valueClass,
       minSplits,
-      cloneKeyValues)
+      cloneRecords)
   }
 
   /**
@@ -394,14 +405,14 @@ class SparkContext(
    * }}}
    */
   def hadoopFile[K, V, F <: InputFormat[K, V]]
-      (path: String, minSplits: Int, cloneKeyValues: Boolean = true)
+      (path: String, minSplits: Int, cloneRecords: Boolean = true)
       (implicit km: ClassTag[K], vm: ClassTag[V], fm: ClassTag[F]): RDD[(K, V)] = {
     hadoopFile(path,
       fm.runtimeClass.asInstanceOf[Class[F]],
       km.runtimeClass.asInstanceOf[Class[K]],
       vm.runtimeClass.asInstanceOf[Class[V]],
       minSplits,
-      cloneKeyValues = cloneKeyValues)
+      cloneRecords)
   }
 
   /**
@@ -412,20 +423,20 @@ class SparkContext(
    * val file = sparkContext.hadoopFile[LongWritable, Text, TextInputFormat](path)
    * }}}
    */
-  def hadoopFile[K, V, F <: InputFormat[K, V]](path: String, cloneKeyValues: Boolean = true)
+  def hadoopFile[K, V, F <: InputFormat[K, V]](path: String, cloneRecords: Boolean = true)
       (implicit km: ClassTag[K], vm: ClassTag[V], fm: ClassTag[F]): RDD[(K, V)] =
-    hadoopFile[K, V, F](path, defaultMinSplits, cloneKeyValues)
+    hadoopFile[K, V, F](path, defaultMinSplits, cloneRecords)
 
   /** Get an RDD for a Hadoop file with an arbitrary new API InputFormat. */
   def newAPIHadoopFile[K, V, F <: NewInputFormat[K, V]]
-      (path: String, cloneKeyValues: Boolean = true)
+      (path: String, cloneRecords: Boolean = true)
       (implicit km: ClassTag[K], vm: ClassTag[V], fm: ClassTag[F]): RDD[(K, V)] = {
     newAPIHadoopFile(
       path,
       fm.runtimeClass.asInstanceOf[Class[F]],
       km.runtimeClass.asInstanceOf[Class[K]],
       vm.runtimeClass.asInstanceOf[Class[V]],
-      cloneKeyValues = cloneKeyValues)
+      cloneRecords = cloneRecords)
   }
 
   /**
@@ -438,11 +449,11 @@ class SparkContext(
       kClass: Class[K],
       vClass: Class[V],
       conf: Configuration = hadoopConfiguration,
-      cloneKeyValues: Boolean = true): RDD[(K, V)] = {
+      cloneRecords: Boolean = true): RDD[(K, V)] = {
     val job = new NewHadoopJob(conf)
     NewFileInputFormat.addInputPath(job, new Path(path))
     val updatedConf = job.getConfiguration
-    new NewHadoopRDD(this, fClass, kClass, vClass, updatedConf, cloneKeyValues)
+    new NewHadoopRDD(this, fClass, kClass, vClass, updatedConf, cloneRecords)
   }
 
   /**
@@ -454,8 +465,8 @@ class SparkContext(
       fClass: Class[F],
       kClass: Class[K],
       vClass: Class[V],
-      cloneKeyValues: Boolean = true): RDD[(K, V)] = {
-    new NewHadoopRDD(this, fClass, kClass, vClass, conf, cloneKeyValues)
+      cloneRecords: Boolean = true): RDD[(K, V)] = {
+    new NewHadoopRDD(this, fClass, kClass, vClass, conf, cloneRecords)
   }
 
   /** Get an RDD for a Hadoop SequenceFile with given key and value types. */
@@ -463,16 +474,16 @@ class SparkContext(
       keyClass: Class[K],
       valueClass: Class[V],
       minSplits: Int,
-      cloneKeyValues: Boolean = true
+      cloneRecords: Boolean = true
       ): RDD[(K, V)] = {
     val inputFormatClass = classOf[SequenceFileInputFormat[K, V]]
-    hadoopFile(path, inputFormatClass, keyClass, valueClass, minSplits, cloneKeyValues)
+    hadoopFile(path, inputFormatClass, keyClass, valueClass, minSplits, cloneRecords)
   }
 
   /** Get an RDD for a Hadoop SequenceFile with given key and value types. */
   def sequenceFile[K: ClassTag, V: ClassTag](path: String, keyClass: Class[K], valueClass: Class[V],
-      cloneKeyValues: Boolean = true): RDD[(K, V)] =
-    sequenceFile(path, keyClass, valueClass, defaultMinSplits, cloneKeyValues)
+      cloneRecords: Boolean = true): RDD[(K, V)] =
+    sequenceFile(path, keyClass, valueClass, defaultMinSplits, cloneRecords)
 
   /**
    * Version of sequenceFile() for types implicitly convertible to Writables through a
@@ -490,17 +501,18 @@ class SparkContext(
    * for the appropriate type. In addition, we pass the converter a ClassTag of its type to
    * allow it to figure out the Writable class to use in the subclass case.
    */
-   def sequenceFile[K, V](path: String, minSplits: Int = defaultMinSplits,
-       cloneKeyValues: Boolean = true) (implicit km: ClassTag[K], vm: ClassTag[V],
-          kcf: () => WritableConverter[K], vcf: () => WritableConverter[V])
+   def sequenceFile[K, V]
+       (path: String, minSplits: Int = defaultMinSplits, cloneRecords: Boolean = true)
+       (implicit km: ClassTag[K], vm: ClassTag[V],
+        kcf: () => WritableConverter[K], vcf: () => WritableConverter[V])
       : RDD[(K, V)] = {
     val kc = kcf()
     val vc = vcf()
     val format = classOf[SequenceFileInputFormat[Writable, Writable]]
     val writables = hadoopFile(path, format,
         kc.writableClass(km).asInstanceOf[Class[Writable]],
-        vc.writableClass(vm).asInstanceOf[Class[Writable]], minSplits, cloneKeyValues)
-    writables.map{case (k,v) => (kc.convert(k), vc.convert(v))}
+        vc.writableClass(vm).asInstanceOf[Class[Writable]], minSplits, cloneRecords)
+    writables.map { case (k, v) => (kc.convert(k), vc.convert(v)) }
   }
 
   /**
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 2da4611b9c0ff64689a958d4ede91c7681c61886..902083c24f088b04239b6bbd89087cf84c9ccf63 100644
--- a/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala
@@ -45,14 +45,14 @@ private[spark] class HadoopPartition(rddId: Int, idx: Int, @transient s: InputSp
 
   val inputSplit = new SerializableWritable[InputSplit](s)
 
-  override def hashCode(): Int = (41 * (41 + rddId) + idx).toInt
+  override def hashCode(): Int = 41 * (41 + rddId) + idx
 
   override val index: Int = idx
 }
 
 /**
  * An RDD that provides core functionality for reading data stored in Hadoop (e.g., files in HDFS,
- * sources in HBase, or S3).
+ * sources in HBase, or S3), using the older MapReduce API (`org.apache.hadoop.mapred`).
  *
  * @param sc The SparkContext to associate the RDD with.
  * @param broadcastedConf A general Hadoop Configuration, or a subclass of it. If the enclosed
@@ -64,6 +64,11 @@ private[spark] class HadoopPartition(rddId: Int, idx: Int, @transient s: InputSp
  * @param keyClass Class of the key associated with the inputFormatClass.
  * @param valueClass Class of the value associated with the inputFormatClass.
  * @param minSplits Minimum number of Hadoop Splits (HadoopRDD partitions) to generate.
+ * @param cloneRecords If true, Spark will clone the records produced by Hadoop RecordReader.
+ *                     Most RecordReader implementations reuse wrapper objects across multiple
+ *                     records, and can cause problems in RDD collect or aggregation operations.
+ *                     By default the records are cloned in Spark. However, application
+ *                     programmers can explicitly disable the cloning for better performance.
  */
 class HadoopRDD[K: ClassTag, V: ClassTag](
     sc: SparkContext,
@@ -73,7 +78,7 @@ class HadoopRDD[K: ClassTag, V: ClassTag](
     keyClass: Class[K],
     valueClass: Class[V],
     minSplits: Int,
-    cloneKeyValues: Boolean)
+    cloneRecords: Boolean)
   extends RDD[(K, V)](sc, Nil) with Logging {
 
   def this(
@@ -83,7 +88,7 @@ class HadoopRDD[K: ClassTag, V: ClassTag](
       keyClass: Class[K],
       valueClass: Class[V],
       minSplits: Int,
-      cloneKeyValues: Boolean) = {
+      cloneRecords: Boolean) = {
     this(
       sc,
       sc.broadcast(new SerializableWritable(conf))
@@ -93,7 +98,7 @@ class HadoopRDD[K: ClassTag, V: ClassTag](
       keyClass,
       valueClass,
       minSplits,
-      cloneKeyValues)
+      cloneRecords)
   }
 
   protected val jobConfCacheKey = "rdd_%d_job_conf".format(id)
@@ -165,9 +170,9 @@ class HadoopRDD[K: ClassTag, V: ClassTag](
       // Register an on-task-completion callback to close the input stream.
       context.addOnCompleteCallback{ () => closeIfNeeded() }
       val key: K = reader.createKey()
-      val keyCloneFunc = cloneWritables[K](getConf)
+      val keyCloneFunc = cloneWritables[K](jobConf)
       val value: V = reader.createValue()
-      val valueCloneFunc = cloneWritables[V](getConf)
+      val valueCloneFunc = cloneWritables[V](jobConf)
       override def getNext() = {
         try {
           finished = !reader.next(key, value)
@@ -175,9 +180,8 @@ class HadoopRDD[K: ClassTag, V: ClassTag](
           case eof: EOFException =>
             finished = true
         }
-        if (cloneKeyValues) {
-          (keyCloneFunc(key.asInstanceOf[Writable]),
-            valueCloneFunc(value.asInstanceOf[Writable]))
+        if (cloneRecords) {
+          (keyCloneFunc(key.asInstanceOf[Writable]), valueCloneFunc(value.asInstanceOf[Writable]))
         } else {
           (key, value)
         }
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 a34786495bd999641044541f6daf40cfdf12e004..992bd4aa0ad5dbc17283048a1f0613a3ea3144b6 100644
--- a/core/src/main/scala/org/apache/spark/rdd/NewHadoopRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/NewHadoopRDD.scala
@@ -36,16 +36,31 @@ class NewHadoopPartition(rddId: Int, val index: Int, @transient rawSplit: InputS
 
   val serializableHadoopSplit = new SerializableWritable(rawSplit)
 
-  override def hashCode(): Int = (41 * (41 + rddId) + index)
+  override def hashCode(): Int = 41 * (41 + rddId) + index
 }
 
+/**
+ * An RDD that provides core functionality for reading data stored in Hadoop (e.g., files in HDFS,
+ * sources in HBase, or S3), using the new MapReduce API (`org.apache.hadoop.mapreduce`).
+ *
+ * @param sc The SparkContext to associate the RDD with.
+ * @param inputFormatClass Storage format of the data to be read.
+ * @param keyClass Class of the key associated with the inputFormatClass.
+ * @param valueClass Class of the value associated with the inputFormatClass.
+ * @param conf The Hadoop configuration.
+ * @param cloneRecords If true, Spark will clone the records produced by Hadoop RecordReader.
+ *                     Most RecordReader implementations reuse wrapper objects across multiple
+ *                     records, and can cause problems in RDD collect or aggregation operations.
+ *                     By default the records are cloned in Spark. However, application
+ *                     programmers can explicitly disable the cloning for better performance.
+ */
 class NewHadoopRDD[K: ClassTag, V: ClassTag](
     sc : SparkContext,
     inputFormatClass: Class[_ <: InputFormat[K, V]],
     keyClass: Class[K],
     valueClass: Class[V],
     @transient conf: Configuration,
-    cloneKeyValues: Boolean)
+    cloneRecords: Boolean)
   extends RDD[(K, V)](sc, Nil)
   with SparkHadoopMapReduceUtil
   with Logging {
@@ -112,9 +127,8 @@ class NewHadoopRDD[K: ClassTag, V: ClassTag](
         havePair = false
         val key = reader.getCurrentKey
         val value = reader.getCurrentValue
-        if (cloneKeyValues) {
-          (keyCloneFunc(key.asInstanceOf[Writable]),
-            valueCloneFunc(value.asInstanceOf[Writable]))
+        if (cloneRecords) {
+          (keyCloneFunc(key.asInstanceOf[Writable]), valueCloneFunc(value.asInstanceOf[Writable]))
         } else {
           (key, value)
         }