--- a/src/jdk.jpackage/share/classes/jdk/jpackage/internal/StandardBundlerParam.java	Fri May 31 08:26:31 2019 -0400
+++ b/src/jdk.jpackage/share/classes/jdk/jpackage/internal/StandardBundlerParam.java	Thu Jun 06 19:07:18 2019 -0400
@@ -161,6 +161,9 @@
                                 BundleParams.PARAM_APPLICATION_CLASS);
                         if (s == null) {
                             s = JLinkBundlerHelper.getMainClass(params);
+                            if (s.length() == 0) {
+                                s = null;
+                            }
                         }
                         return s;
                     },