Program: 11908
Project: 11908
Buggy source:
TridentWorld(String name,WorldLoader loader){
  this.name=name;
  this.loader=loader;
  this.random=new Random();
  spawnLocation=new Location(this,0d,0d,0d);
  Logger logger=LoggerFactory.getLogger(TridentServer.class);
  logger.info("String_Node_Str" + name + "String_Node_Str");
  logger.info("String_Node_Str");
  File directory=new File(name + File.separator);
  File levelFile=new File(directory,"String_Node_Str");
  CompoundTag level;
  try {
    InputStream fis=new FileInputStream(levelFile);
    byte[] compressedData=new byte[fis.available()];
    fis.read(compressedData);
    level=new NBTDecoder(new DataInputStream(new ByteArrayInputStream(ByteStreams.toByteArray(new GZIPInputStream(new ByteArrayInputStream(compressedData)))))).decode().getTagAs("String_Node_Str");
  }
 catch (  FileNotFoundException ignored) {
    return;
  }
catch (  Exception ex) {
    logger.info("String_Node_Str");
    ex.printStackTrace();
    return;
  }
  logger.info("String_Node_Str");
  spawnLocation.setX(((IntTag)level.getTag("String_Node_Str")).getValue());
  spawnLocation.setY(((IntTag)level.getTag("String_Node_Str")).getValue());
  spawnLocation.setZ(((IntTag)level.getTag("String_Node_Str")).getValue());
  dimension=Dimension.OVERWORLD;
  difficulty=Difficulty.NORMAL;
  defaultGamemode=GameMode.getGameMode(((IntTag)level.getTag("String_Node_Str")).getValue());
  type=LevelType.getLevelType(((StringTag)level.getTag("String_Node_Str")).getValue());
  logger.info("String_Node_Str");
  File region=new File(directory,"String_Node_Str" + File.separator);
  if (!(region.exists()) || !(region.isDirectory())) {
    throw new IllegalStateException("String_Node_Str");
  }
  for (  File file : region.listFiles(new ChunkFilter())) {
    String[] strings=file.getName().split("String_Node_Str");
    int chunkX=(int)Math.floor(Integer.parseInt(strings[1]) * 32);
    int chunkZ=(int)Math.floor(Integer.parseInt(strings[2]) * 32);
    logger.info("String_Node_Str" + file.getName() + "String_Node_Str");
    RegionFile regionFile;
    try {
      regionFile=new RegionFile(file.toPath());
    }
 catch (    IOException ex) {
      logger.info("String_Node_Str");
      ex.printStackTrace();
      continue;
    }
    ChunkLocation location=new ChunkLocation(chunkX,chunkZ);
    TridentChunk chunk;
    try {
      chunk=regionFile.loadChunkData(this,location);
    }
 catch (    NBTException|IOException|DataFormatException e) {
      logger.info("String_Node_Str");
      e.printStackTrace();
      continue;
    }
    loadedChunks.put(location,chunk);
    logger.info("String_Node_Str" + file.getName() + "String_Node_Str");
  }
  logger.info("String_Node_Str");
  File playerData=new File(directory,"String_Node_Str");
  if (!(playerData.exists()) || !(playerData.isDirectory())) {
    logger.info("String_Node_Str");
    playerData.mkdir();
  }
 else {
    logger.info("String_Node_Str");
    for (    File f : playerData.listFiles(new PlayerFilter())) {
      CompoundTag opData;
      try {
        InputStream fis=new FileInputStream(levelFile);
        byte[] compressedData=new byte[fis.available()];
        fis.read(compressedData);
        opData=new NBTDecoder(new DataInputStream(new ByteArrayInputStream(ByteStreams.toByteArray(new GZIPInputStream(new ByteArrayInputStream(compressedData)))))).decode();
      }
 catch (      IOException|NBTException ex) {
        logger.info("String_Node_Str" + f.getName() + "String_Node_Str");
        ex.printStackTrace();
        continue;
      }
      new OfflinePlayer(opData,this);
    }
    logger.info("String_Node_Str");
  }
}

Fixed version (ground truth):
TridentWorld(String name,WorldLoader loader){
  this.name=name;
  this.loader=loader;
  this.random=new Random();
  spawnLocation=new Location(this,0d,0d,0d);
  Logger logger=LoggerFactory.getLogger(TridentServer.class);
  logger.info("String_Node_Str" + name + "String_Node_Str");
  logger.info("String_Node_Str");
  File directory=new File(name + File.separator);
  File levelFile=new File(directory,"String_Node_Str");
  CompoundTag level;
  try {
    InputStream fis=new FileInputStream(levelFile);
    byte[] compressedData=new byte[fis.available()];
    fis.read(compressedData);
    level=new NBTDecoder(new DataInputStream(new ByteArrayInputStream(ByteStreams.toByteArray(new GZIPInputStream(new ByteArrayInputStream(compressedData)))))).decode().getTagAs("String_Node_Str");
  }
 catch (  FileNotFoundException ignored) {
    return;
  }
catch (  Exception ex) {
    logger.info("String_Node_Str");
    ex.printStackTrace();
    return;
  }
  logger.info("String_Node_Str");
  spawnLocation.setX(((IntTag)level.getTag("String_Node_Str")).getValue());
  spawnLocation.setY(((IntTag)level.getTag("String_Node_Str")).getValue());
  spawnLocation.setZ(((IntTag)level.getTag("String_Node_Str")).getValue());
  dimension=Dimension.OVERWORLD;
  difficulty=Difficulty.NORMAL;
  defaultGamemode=GameMode.getGameMode(((IntTag)level.getTag("String_Node_Str")).getValue());
  type=LevelType.getLevelType(((StringTag)level.getTag("String_Node_Str")).getValue());
  logger.info("String_Node_Str");
  File region=new File(directory,"String_Node_Str" + File.separator);
  if (!(region.exists()) || !(region.isDirectory())) {
    throw new IllegalStateException("String_Node_Str");
  }
  logger.info("String_Node_Str");
  File playerData=new File(directory,"String_Node_Str");
  if (!(playerData.exists()) || !(playerData.isDirectory())) {
    logger.info("String_Node_Str");
    playerData.mkdir();
  }
 else {
    logger.info("String_Node_Str");
    for (    File f : playerData.listFiles(new PlayerFilter())) {
      CompoundTag opData;
      try {
        InputStream fis=new FileInputStream(levelFile);
        byte[] compressedData=new byte[fis.available()];
        fis.read(compressedData);
        opData=new NBTDecoder(new DataInputStream(new ByteArrayInputStream(ByteStreams.toByteArray(new GZIPInputStream(new ByteArrayInputStream(compressedData)))))).decode();
      }
 catch (      IOException|NBTException ex) {
        logger.info("String_Node_Str" + f.getName() + "String_Node_Str");
        ex.printStackTrace();
        continue;
      }
      new OfflinePlayer(opData,this);
    }
    logger.info("String_Node_Str");
  }
}