private DirCache createIndex(Repository db, long ticketId, Change change)
throws IOException, ClassNotFoundException, NoSuchFieldException {
String ticketPath = toTicketPath(ticketId);
DirCache newIndex = DirCache.newInCore();
DirCacheBuilder builder = newIndex.builder();
ObjectInserter inserter = db.newObjectInserter();
Set<String> ignorePaths = new TreeSet<String>();
try {
// create/update the journal