使用Java Desktop.open（文件f）并知道应用程序已完成

It appears that using the Java Desktop.open( File f ) to open a file with the default app that it is associated to on the user's desktop does not give me information on when the user is done with this file. How would one find out when ther user has truly finished with this child process ? Is there something more elegant than checking the file size every once in a while - something that only tells me that the file has been saved.It appears that using the Java Desktop.open( Fi