使用Preloader JavaFx将JAR文件捆绑到应用程序包中

I'm trying to create an app package with preloader class using ant. With the following build.xml file the app is successfully created. After double click on Viewer.app the preloader screen doesn't appear. When I start the application directly with java -jar Viewer.jar the preloader screen can be ssen on windows os and mac os. I'm trying to create an app package with preloa