Not a real task but used during tests.
Closes the resources associated with an URL. In particular this is
going to close the jars associated with a jar:file: URL - and it
does so in a way that the Java VM still thinks it is open, so use
it at your own risk.
Fields inherited from class org.apache.tools.ant.Task
Called by the project to let the task do its work. This method may be
called more than once, if the task is invoked more than once.
if target1 and target2 both depend on target3, then running
"ant target1 target2" will run all tasks in target3 twice.