Program: 152165
Project: 152165
Buggy source:
public void handlePacket(Packet p,IoSession session) throws Exception {
  final long uID=((LSPacket)p).getUID();
  builder.setUID(uID);
  builder.setSuccess(false);
  Server server=Server.getServer();
  if (((LSPacket)p).getID() == 1) {
    int id=p.readShort();
    if (server.getWorld(id) == null) {
      World world=server.getIdleWorld(id);
      if (world == null) {
        world=new World(id,session);
        if (!Server.devMode) {
          int passL=p.readInt();
          byte[] pass=p.readBytes(passL);
          if (!Arrays.equals(new Hash(Config.LS_CONNECT_PASS.getBytes()).value(),pass)) {
            System.out.println("String_Node_Str");
            LSPacket temp=builder.getPacket();
            if (temp != null) {
              session.write(temp);
            }
            return;
          }
        }
 else {
          int length=p.readInt();
          if (length != 0) {
            System.out.println("String_Node_Str");
          }
          LSPacket temp=builder.getPacket();
          if (temp != null) {
            session.write(temp);
          }
          return;
        }
        server.registerWorld(world);
        System.out.println("String_Node_Str" + id);
      }
 else {
        world.setSession(session);
        server.setIdle(world,false);
        System.out.println("String_Node_Str" + id);
      }
      int playerCount=p.readShort();
      for (int i=0; i < playerCount; i++) {
        world.registerPlayer(p.readLong(),DataConversions.IPToString(p.readLong()),p.readString(p.readInt()));
      }
      session.setAttachment(world);
      builder.setSuccess(true);
    }
  }
 else {
    World world=(World)session.getAttachment();
    server.unregisterWorld(world);
    System.out.println("String_Node_Str" + world.getID());
    session.setAttachment(null);
    builder.setSuccess(true);
  }
  LSPacket temp=builder.getPacket();
  if (temp != null) {
    session.write(temp);
  }
}

Fixed version (ground truth):
public void handlePacket(Packet p,IoSession session) throws Exception {
  final long uID=((LSPacket)p).getUID();
  builder.setUID(uID);
  builder.setSuccess(false);
  Server server=Server.getServer();
  if (((LSPacket)p).getID() == 1) {
    int id=p.readShort();
    if (server.getWorld(id) == null) {
      World world=server.getIdleWorld(id);
      if (world == null) {
        world=new World(id,session);
        if (!Server.devMode) {
          int passL=p.readInt();
          byte[] pass=p.readBytes(passL);
          if (!Arrays.equals(new Hash(Config.LS_CONNECT_PASS.getBytes()).value(),pass)) {
            System.out.println("String_Node_Str");
            LSPacket temp=builder.getPacket();
            if (temp != null) {
              session.write(temp);
            }
            return;
          }
        }
 else {
          int length=p.readInt();
          if (length != 0) {
            System.out.println("String_Node_Str");
            LSPacket temp=builder.getPacket();
            if (temp != null) {
              session.write(temp);
            }
            return;
          }
        }
        server.registerWorld(world);
        System.out.println("String_Node_Str" + id);
      }
 else {
        world.setSession(session);
        server.setIdle(world,false);
        System.out.println("String_Node_Str" + id);
      }
      int playerCount=p.readShort();
      for (int i=0; i < playerCount; i++) {
        world.registerPlayer(p.readLong(),DataConversions.IPToString(p.readLong()),p.readString(p.readInt()));
      }
      session.setAttachment(world);
      builder.setSuccess(true);
    }
  }
 else {
    World world=(World)session.getAttachment();
    server.unregisterWorld(world);
    System.out.println("String_Node_Str" + world.getID());
    session.setAttachment(null);
    builder.setSuccess(true);
  }
  LSPacket temp=builder.getPacket();
  if (temp != null) {
    session.write(temp);
  }
}