Java SE (Java Platform, Standard Edition)

I'm new to Java/JavaFX/XML although a long time programmer of legacy languages. The tutorial is a bit scant on the use of Ant tasks. I understand the syntax of tasks for JavaFX through examples I have reviewed and I gather that tasks have to be written in files with .xml extension. Want I can't figure out is how to run the tasks in the build.xml file I created, to produce the .jar file.