Found in a young Java fanatic's dropbox. Reinventing the ObjectOutputStream wheel.

byteAbuse.java

  private static void put(Preferences prefs, String key, byte[] bytes) {
    final int maxBytesPerKey = byteArrLen();
    final int keysNeeded = (int) Math.ceil((float) bytes.length / (float) maxBytesPerKey);
    final int remainderBytes = bytes.length % maxBytesPerKey;
    byte[][] splitBytes = new byte[keysNeeded][maxBytesPerKey];
    splitBytes[keysNeeded-1] = new byte[remainderBytes];
    for (int keyNum=0; keyNum < keysNeeded; keyNum++) {
      for (int b=0; b < splitBytes[keyNum].length; b++) {
        splitBytes[keyNum][b] = bytes[(keyNum * maxBytesPerKey) + b];
      }
    }
    // splitBytes now populated properly
    prefs.putInt("keys", keysNeeded);
    prefs.putInt("bytes", (keysNeeded * (maxBytesPerKey-1)) + remainderBytes);
    for (Integer keyNum=0; keyNum < keysNeeded; keyNum++) {
      prefs.putByteArray(keyNum.toString(), splitBytes[keyNum]);
    }
  }
   
  private static byte[] get(Preferences prefs, String key) {
    byte[] bytes = new byte[prefs.getInt("bytes", 1)];
    int bytesIndex = 0;
    int keys = prefs.getInt("keys", 1);
    for (Integer keyNum = 0; keyNum < keys; keyNum++) {
      byte[] chunk = prefs.getByteArray(keyNum.toString(), null);
      if (chunk == null) {
        //new Exception("Chunk is null! Oh noes!").printStackTrace();
        continue;
      }
      for (int i=0; i<chunk.length && bytesIndex < bytes.length; i++) {
        bytes[bytesIndex] = chunk[i];
        bytesIndex++;
      }
    }
    return bytes;
  }