Program: 156023
Project: 156023
Buggy source:
private Position decodeU01(String sentence,Channel channel,SocketAddress remoteAddress){
  Parser parser=new Parser(PATTERN_U01,sentence);
  if (!parser.matches()) {
    return null;
  }
  DeviceSession deviceSession=getDeviceSession(channel,remoteAddress,parser.next());
  if (deviceSession == null) {
    return null;
  }
  String messageType=parser.next();
  Position position=new Position();
  position.setProtocol(getProtocolName());
  position.setDeviceId(deviceSession.getDeviceId());
  DateBuilder dateBuilder=new DateBuilder().setDateReverse(parser.nextInt(),parser.nextInt(),parser.nextInt()).setTime(parser.nextInt(),parser.nextInt(),parser.nextInt());
  position.setTime(dateBuilder.getDate());
  position.setValid(parser.next().equals("String_Node_Str"));
  position.setLatitude(parser.nextCoordinate(Parser.CoordinateFormat.DEG_HEM));
  position.setLongitude(parser.nextCoordinate(Parser.CoordinateFormat.DEG_HEM));
  position.setSpeed(UnitsConverter.knotsFromMph(parser.nextDouble()));
  position.setCourse(parser.nextDouble());
  position.set(Position.KEY_SATELLITES,parser.nextInt());
  position.set(Position.KEY_BATTERY,parser.next());
  position.set(Position.KEY_STATUS,parser.nextInt(2));
  position.set(Position.KEY_CID,parser.nextInt());
  position.set(Position.KEY_LAC,parser.nextInt());
  position.set(Position.KEY_GSM,parser.nextInt());
  position.set(Position.KEY_ODOMETER,parser.nextLong() * 1000);
  position.set(Position.KEY_INDEX,parser.nextInt());
switch (messageType) {
case "String_Node_Str":
case "String_Node_Str":
case "String_Node_Str":
    if (parser.hasNext(2)) {
      int checkSum=parser.nextInt(16);
      int calculatedCheckSum=Checksum.xor(sentence.substring(1,sentence.length() - 3));
      if (checkSum == calculatedCheckSum) {
        sendResponse(channel,"String_Node_Str");
        return position;
      }
 else {
        return null;
      }
    }
 else {
      return position;
    }
case "String_Node_Str":
  sendResponse(channel,"String_Node_Str");
return position;
default :
return null;
}
}

Fixed version (ground truth):
private Position decodeU01(String sentence,Channel channel,SocketAddress remoteAddress){
  Parser parser=new Parser(PATTERN_U01,sentence);
  if (!parser.matches()) {
    return null;
  }
  DeviceSession deviceSession=getDeviceSession(channel,remoteAddress,parser.next());
  if (deviceSession == null) {
    return null;
  }
  String type=parser.next();
  Position position=new Position();
  position.setProtocol(getProtocolName());
  position.setDeviceId(deviceSession.getDeviceId());
  DateBuilder dateBuilder=new DateBuilder().setDateReverse(parser.nextInt(),parser.nextInt(),parser.nextInt()).setTime(parser.nextInt(),parser.nextInt(),parser.nextInt());
  position.setTime(dateBuilder.getDate());
  position.setValid(parser.next().equals("String_Node_Str"));
  position.setLatitude(parser.nextCoordinate(Parser.CoordinateFormat.DEG_HEM));
  position.setLongitude(parser.nextCoordinate(Parser.CoordinateFormat.DEG_HEM));
  position.setSpeed(UnitsConverter.knotsFromMph(parser.nextDouble()));
  position.setCourse(parser.nextDouble());
  position.set(Position.KEY_SATELLITES,parser.nextInt());
  position.set(Position.KEY_BATTERY,parser.next());
  position.set(Position.KEY_STATUS,parser.nextInt(2));
  position.set(Position.KEY_CID,parser.nextInt());
  position.set(Position.KEY_LAC,parser.nextInt());
  position.set(Position.KEY_GSM,parser.nextInt());
  position.set(Position.KEY_ODOMETER,parser.nextLong() * 1000);
  position.set(Position.KEY_INDEX,parser.nextInt());
  if (channel != null) {
    if (type.equals("String_Node_Str") || type.equals("String_Node_Str") || type.equals("String_Node_Str")) {
      channel.write("String_Node_Str");
    }
 else     if (type.equals("String_Node_Str")) {
      channel.write("String_Node_Str");
    }
  }
  return position;
}