Program: 71048
Project: 71048
Buggy source:
@EventHandler public void onPlayerJoin(PlayerJoinEvent event){
  Player player=event.getPlayer();
  event.setJoinMessage(null);
  PacketPlayerInfo packet=PlayerInfoHolder.getPlayerInfos().get(player.getUniqueId());
  if (packet == null)   return;
  try {
    if (packet.getInventory() != null)     player.getInventory().setContents(Serializer.deserializeInventory(packet.getInventory()));
    if (packet.getArmorContents() != null)     player.getInventory().setArmorContents(Serializer.deserializeInventory(packet.getArmorContents()));
    if (packet.getEnderContents() != null)     player.getEnderChest().setContents(Serializer.deserializeInventory(packet.getEnderContents()));
  }
 catch (  IOException e) {
    StackTraceHandler.handle(OpenSectorLinker.class,e,StackTraceSeverity.ERROR);
  }
  SerializablePotionEffect[] potionEffects=packet.getPotionEffects();
  Location destination=new Location(player.getWorld(),packet.getX(),packet.getY(),packet.getZ(),packet.getYaw(),packet.getPitch());
  player.teleport(Util.getValidLocation(destination,packet.getY()));
  if (potionEffects != null) {
    for (    SerializablePotionEffect potionEffect : potionEffects) {
      PotionEffect effect=new PotionEffect(PotionEffectType.getByName(potionEffect.getPotionEffectType()),potionEffect.getDuration(),potionEffect.getAmplifier());
      player.addPotionEffect(effect);
    }
  }
  player.setHealth(packet.getHealth());
  player.setFoodLevel((int)packet.getFood());
  player.setExp((float)packet.getExp());
  player.setLevel((int)packet.getLevel());
  player.setAllowFlight(packet.isFly());
  player.setGameMode(GameMode.valueOf(packet.getGameMode()));
  player.getInventory().setHeldItemSlot(packet.getHeldSlot());
  ServerController controller=OpenSectorLinker.getServerController(OpenSectorLinker.getServerId());
  for (  String str : OpenSectorLinker.getInstance().getConfig().getStringList("String_Node_Str")) {
    player.sendMessage(Util.fixColors(str.replace("String_Node_Str",String.valueOf(controller.id)).replace("String_Node_Str",controller.name)));
  }
}

Fixed version (ground truth):
@EventHandler public void onPlayerJoin(PlayerJoinEvent event){
  Player player=event.getPlayer();
  event.setJoinMessage(null);
  PacketPlayerInfo packet=PlayerInfoHolder.getPlayerInfos().get(player.getUniqueId());
  if (packet == null)   return;
  try {
    if (packet.getInventory() != null)     player.getInventory().setContents(Serializer.deserializeInventory(packet.getInventory()));
 else     player.getInventory().clear();
    if (packet.getArmorContents() != null)     player.getInventory().setArmorContents(Serializer.deserializeInventory(packet.getArmorContents()));
    if (packet.getEnderContents() != null)     player.getEnderChest().setContents(Serializer.deserializeInventory(packet.getEnderContents()));
  }
 catch (  IOException e) {
    StackTraceHandler.handle(OpenSectorLinker.class,e,StackTraceSeverity.ERROR);
  }
  SerializablePotionEffect[] potionEffects=packet.getPotionEffects();
  Location destination=new Location(player.getWorld(),packet.getX(),packet.getY(),packet.getZ(),packet.getYaw(),packet.getPitch());
  player.teleport(Util.getValidLocation(destination,packet.getY()));
  if (potionEffects != null) {
    for (    SerializablePotionEffect potionEffect : potionEffects) {
      PotionEffect effect=new PotionEffect(PotionEffectType.getByName(potionEffect.getPotionEffectType()),potionEffect.getDuration(),potionEffect.getAmplifier());
      player.addPotionEffect(effect);
    }
  }
  player.setHealth(packet.getHealth());
  player.setFoodLevel((int)packet.getFood());
  player.setExp((float)packet.getExp());
  player.setLevel((int)packet.getLevel());
  player.setAllowFlight(packet.isFly());
  player.setGameMode(GameMode.valueOf(packet.getGameMode()));
  player.getInventory().setHeldItemSlot(packet.getHeldSlot());
  ServerController controller=OpenSectorLinker.getServerController(OpenSectorLinker.getServerId());
  for (  String str : OpenSectorLinker.getInstance().getConfig().getStringList("String_Node_Str")) {
    player.sendMessage(Util.fixColors(str.replace("String_Node_Str",String.valueOf(controller.id)).replace("String_Node_Str",controller.name)));
  }
  PlayerInfoHolder.getPlayerInfos().remove(player.getUniqueId());
}