1 files changed, 8 insertions, 4 deletions
diff --git a/core/src/main/scala/spark/JavaSerializer.scala b/core/src/main/scala/spark/JavaSerializer.scala
index d11ba5167d..b04a27d073 100644
--- a/core/src/main/scala/spark/JavaSerializer.scala
+++ b/core/src/main/scala/spark/JavaSerializer.scala
@@ -3,16 +3,17 @@ package spark
 import java.io._
 import java.nio.ByteBuffer
 
+import serializer.{Serializer, SerializerInstance, DeserializationStream, SerializationStream}
 import spark.util.ByteBufferInputStream
 
-class JavaSerializationStream(out: OutputStream) extends SerializationStream {
+private[spark] class JavaSerializationStream(out: OutputStream) extends SerializationStream {
   val objOut = new ObjectOutputStream(out)
-  def writeObject[T](t: T) { objOut.writeObject(t) }
+  def writeObject[T](t: T): SerializationStream = { objOut.writeObject(t); this }
   def flush() { objOut.flush() }
   def close() { objOut.close() }
 }
 
-class JavaDeserializationStream(in: InputStream, loader: ClassLoader)
+private[spark] class JavaDeserializationStream(in: InputStream, loader: ClassLoader)
 extends DeserializationStream {
   val objIn = new ObjectInputStream(in) {
     override def resolveClass(desc: ObjectStreamClass) =
@@ -23,7 +24,7 @@ extends DeserializationStream {
   def close() { objIn.close() }
 }
 
-class JavaSerializerInstance extends SerializerInstance {
+private[spark] class JavaSerializerInstance extends SerializerInstance {
   def serialize[T](t: T): ByteBuffer = {
     val bos = new ByteArrayOutputStream()
     val out = serializeStream(bos)
@@ -57,6 +58,9 @@ class JavaSerializerInstance extends SerializerInstance {
   }
 }
 
+/**
+ * A Spark serializer that uses Java's built-in serialization.
+ */
 class JavaSerializer extends Serializer {
   def newInstance(): SerializerInstance = new JavaSerializerInstance
 }