diff --git a/test/src/test/java/jenkins/security/Security218Test.java b/test/src/test/java/jenkins/security/Security218Test.java
index 3cdeb5868c22d06a85f3123f51d7272c6ef226e6..7d4facc44a06d4d392eb47ad03e5600f9a1b3257 100644
--- a/test/src/test/java/jenkins/security/Security218Test.java
+++ b/test/src/test/java/jenkins/security/Security218Test.java
@@ -31,7 +31,7 @@ public class Security218Test implements Serializable {
     /**
      * JNLP slave.
      */
-    private Process jnlp;
+    private transient Process jnlp;
 
     /**
      * Makes sure SECURITY-218 fix also applies to slaves.