String url=urls.get(options_list.getSelectionModel().getSelectedIndex());
String filename = file.getAbsolutePath();
DownloadManager downloadManager = DownloadManager.getInstance();
DownloadMission mission = new DownloadMission(url,"",filename);
downloadManager.addMission(mission);
downloadManager.start();
java.lang.StringIndexOutOfBoundsException: String index out of range: -1
My code looks like this