diff --git a/core/src/main/scala/spark/Utils.scala b/core/src/main/scala/spark/Utils.scala
index 1cfaee79b19eb3109e0da6d11650971bec9510dd..96d86647f82dcf625d6fd774ceaf945e96af78b1 100644
--- a/core/src/main/scala/spark/Utils.scala
+++ b/core/src/main/scala/spark/Utils.scala
@@ -522,8 +522,8 @@ private object Utils extends Logging {
     execute(command, new File("."))
   }
 
-  class CallSiteInfo(val lastSparkMethod: String, val firstUserFile: String, 
-                      val firstUserLine: Int, val firstUserClass: String)
+  private[spark] class CallSiteInfo(val lastSparkMethod: String, val firstUserFile: String, 
+                                    val firstUserLine: Int, val firstUserClass: String)
   /**
    * When called inside a class in the spark package, returns the name of the user code class
    * (outside the spark package) that called into Spark, as well as which Spark method they called.