private static long[] readHash(String fileName) throws SMatchException {
   try {
     return (long[]) MiscUtils.readObject(fileName);
   } catch (DISIException e) {
     throw new SMatchException(e.getMessage(), e);
   }
 }
 private static void convertAndWrite(Set<Long> keys, String fileName) throws SMatchException {
   try {
     long[] keysArr = new long[keys.size()];
     int i = 0;
     for (Long key : keys) {
       keysArr[i] = key;
       i++;
     }
     Arrays.sort(keysArr);
     MiscUtils.writeObject(keysArr, fileName);
   } catch (DISIException e) {
     throw new SMatchException(e.getClass().getSimpleName() + ": " + e.getMessage(), e);
   }
 }