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 666b2a701123e..d498f0c28577e 100644
--- a/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala
@@ -118,7 +118,7 @@ class HadoopRDD[K, V](
   protected val inputFormatCacheKey = "rdd_%d_input_format".format(id)
 
   // used to build JT ID
-  protected val createTime = new Date()
+  private val createTime = new Date()
 
   // Returns a JobConf that will be used on slaves to obtain input splits for Hadoop reads.
   protected def getJobConf(): JobConf = {