diff -r 278e1c6c3e99 -r 1753108d07b9 test/jdk/java/net/httpclient/MappingResponseSubscriber.java
--- a/test/jdk/java/net/httpclient/MappingResponseSubscriber.java	Fri Mar 02 15:14:03 2018 +0000
+++ b/test/jdk/java/net/httpclient/MappingResponseSubscriber.java	Sat Mar 03 09:54:31 2018 +0000
@@ -30,7 +30,9 @@
  *          java.net.http/jdk.internal.net.http.common
  *          java.net.http/jdk.internal.net.http.frame
  *          java.net.http/jdk.internal.net.http.hpack
- * @run testng/othervm MappingResponseSubscriber
+ * @run testng/othervm
+ *       -Djdk.internal.httpclient.debug=true
+ *      MappingResponseSubscriber
  */
 
 import java.io.IOException;