question: private synchronized void addTracker ( String path , Object marker , FileDeleteStrategy deleteStrategy ) { if ( exitWhenFinished ) { throw new IllegalStateException ( "No new trackers can be added once exitWhenFinished() is called" ) ; } if ( reaper == null ) { reaper = new Reaper ( ) ; reaper . start ( ) ; } trackers . add ( new Tracker ( path , deleteStrategy , marker , q ) ) ; }
target:  Adds a tracker to the list of trackers.