diff --git a/client/src/main/java/org/jboss/fuse/mvnd/client/DefaultClient.java b/client/src/main/java/org/jboss/fuse/mvnd/client/DefaultClient.java
index fe1d2f56..2352ba05 100644
--- a/client/src/main/java/org/jboss/fuse/mvnd/client/DefaultClient.java
+++ b/client/src/main/java/org/jboss/fuse/mvnd/client/DefaultClient.java
@@ -141,7 +141,7 @@ public class DefaultClient implements Client {
                     if (eqPos >= 0) {
                         commandLineProperties.setProperty(arg.substring(2, eqPos), arg.substring(eqPos+1));
                     } else {
-                        commandLineProperties.setProperty(arg.substring(2), null);
+                        commandLineProperties.setProperty(arg.substring(2), "");
                     }
                 }
                 args.add(arg);