diff --git a/core/src/main/scala/spark/SparkEnv.scala b/core/src/main/scala/spark/SparkEnv.scala
index 9ac59918ccc8169be82f66d106a511462f444627..0adbf1d96e9d38f2ba502e85287297902d3b4da8 100644
--- a/core/src/main/scala/spark/SparkEnv.scala
+++ b/core/src/main/scala/spark/SparkEnv.scala
@@ -97,7 +97,7 @@ class SparkEnv (
 
 object SparkEnv extends Logging {
   private val env = new ThreadLocal[SparkEnv]
-  private var lastSetSparkEnv : SparkEnv = _
+  @volatile private var lastSetSparkEnv : SparkEnv = _
 
   def set(e: SparkEnv) {
 	  lastSetSparkEnv = e