Any file with a .xml extension can be run as an Ant buildfile. Of course, not all such files really are Ant buildfiles, but no harm is done if an attempt is made to mistakenly run a non-Ant .xml file as an Ant buildfile.
In this section, the basic mechanisms for running Ant buildfiles in Eclipse will be covered, using the HelloWorld.xml file created in the last section.
Fortunately, if the buildfile is run so that the Hello target is executed first and other times so that the World target is first, the dialog does not need to be brought up each time nor does the ordering need to be changed.