Program: 11915
Project: 11915
Buggy source:
TridentWorld(String name,WorldLoader loader){
  this.name=name;
  this.loader=loader;
  this.random=new Random();
  spawnLocation=new Location(this,0d,0d,0d);
  TridentLogger logger=Trident.getLogger();
  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 {
    level=new NBTDecoder(new DataInputStream(new FileInputStream(levelFile))).decode().getTagAs("String_Node_Str");
  }
 catch (  FileNotFoundException ignored) {
    return;
  }
catch (  NBTException 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.getDifficulty(((IntTag)level.getTag("String_Node_Str")).getValue());
  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()) {
    String[] strings=file.getName().split("String_Node_Str");
    logger.info("String_Node_Str" + file.getName() + "String_Node_Str");
    if (strings.length != 3 && !(strings[0].equals("String_Node_Str")) && !(file.getName().endsWith("String_Node_Str"))) {
      continue;
    }
    int chunkX;
    int chunkZ;
    try {
      chunkX=(int)Math.floor(Integer.parseInt(strings[1]) * 32);
      chunkZ=(int)Math.floor(Integer.parseInt(strings[2]) * 32);
    }
 catch (    NumberFormatException ex) {
      continue;
    }
    for (    ChunkLocation loc : loadedChunks.keySet()) {
      if (loc.getX() == chunkX && loc.getZ() == chunkZ)       continue;
    }
    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);
    }
 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");
  }
}

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);
    GZIPInputStream gzis=new GZIPInputStream(new ByteArrayInputStream(compressedData));
    byte[] decompressed=new byte[gzis.available()];
    gzis.read(decompressed);
    level=new NBTDecoder(new DataInputStream(new ByteArrayInputStream(decompressed))).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.getDifficulty(((IntTag)level.getTag("String_Node_Str")).getValue());
  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()) {
    String[] strings=file.getName().split("String_Node_Str");
    logger.info("String_Node_Str" + file.getName() + "String_Node_Str");
    if (strings.length != 3 && !(strings[0].equals("String_Node_Str")) && !(file.getName().endsWith("String_Node_Str"))) {
      continue;
    }
    int chunkX;
    int chunkZ;
    try {
      chunkX=(int)Math.floor(Integer.parseInt(strings[1]) * 32);
      chunkZ=(int)Math.floor(Integer.parseInt(strings[2]) * 32);
    }
 catch (    NumberFormatException ex) {
      continue;
    }
    for (    ChunkLocation loc : loadedChunks.keySet()) {
      if (loc.getX() == chunkX && loc.getZ() == chunkZ)       continue;
    }
    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);
    }
 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");
  }
}