private void logEntries(Collection<HistoryEntry> entries) {
   LocalHistory.LOG.log(Level.FINE, "LocalHistory returns {0} entries", entries.size()); // NOI18N
   if (LocalHistory.LOG.isLoggable(Level.FINEST)) {
     StringBuilder sb = new StringBuilder();
     Iterator<HistoryEntry> it = entries.iterator();
     while (it.hasNext()) {
       HistoryEntry entry = it.next();
       sb.append("["); // NOI18N
       sb.append(DateFormat.getDateTimeInstance().format(entry.getDateTime()));
       sb.append(",["); // NOI18N
       sb.append(toString(entry.getFiles()));
       sb.append("]]"); // NOI18N
       if (it.hasNext()) sb.append(","); // NOI18N
     }
     LocalHistory.LOG.finest(sb.toString());
   }
 }