Build project into a JAR automatically in Eclipse

I have an Eclipse project where I want to keep my Java project built into a JAR automatically. I know I have an option to export the project into a JAR; if I do a right click; but what I am really looking for is, that like Eclipse automatically builds a project's `.class` files and put them in target folder; it should also build a JAR automatically and copy the latest JAR at some or a specific location. Is there a option to configure Eclipse in such a way, to build JARs automatically? Just to make it clear for guys, patient enough to answer my question; I am not looking at ANT as solution; as I already use it, but what I would like it something that gets initiated automatically either with a time based trigger or immediate build with change.