Program: 1986
Project: 1986
Buggy source:
/** 
 * Displays a list of buying/selling items for the selected trader npc.
 * @param player
 * @param npc
 * @param args
 * @param selling
 */
private void displayList(Player player,HumanNPC npc,String[] args,boolean selling){
  ArrayList<Stockable> stock=npc.getTrader().getStockables(selling);
  int page=0;
  int startPoint=0;
  int numPages=stock.size() / 4;
  if (numPages == 0)   numPages=1;
  String keyword="String_Node_Str";
  if (selling)   keyword="String_Node_Str";
 else   keyword="String_Node_Str";
  if (stock.size() == 0) {
    player.sendMessage(ChatColor.GRAY + "String_Node_Str" + keyword.toLowerCase()+ "String_Node_Str");
    return;
  }
  if (stock.size() > 4 && args.length == 3) {
    page=Integer.parseInt(args[2]);
    startPoint=(4 * page) - 1;
  }
  if (startPoint > stock.size() - 1) {
    player.sendMessage(ChatColor.RED + "String_Node_Str" + StringUtils.yellowify(numPages,ChatColor.RED)+ "String_Node_Str");
    return;
  }
  player.sendMessage(ChatColor.GOLD + "String_Node_Str" + keyword+ "String_Node_Str"+ StringUtils.yellowify((page == 0 ? 1 : page),ChatColor.GOLD)+ "String_Node_Str"+ StringUtils.yellowify(numPages,ChatColor.GOLD)+ "String_Node_Str");
  player.sendMessage(ChatColor.AQUA + "String_Node_Str");
  for (int i=startPoint; i != startPoint + 3; ++i) {
    if ((stock.size() - 1) >= i) {
      Stockable s=stock.get(i);
      player.sendMessage(ChatColor.GREEN + keyword + "String_Node_Str"+ MessageUtils.getStockableMessage(s,ChatColor.GREEN)+ "String_Node_Str");
    }
 else {
      player.sendMessage(ChatColor.AQUA + "String_Node_Str");
      break;
    }
  }
}

Fixed version (ground truth):
/** 
 * Displays a list of buying/selling items for the selected trader npc.
 * @param player
 * @param npc
 * @param args
 * @param selling
 */
private void displayList(Player player,HumanNPC npc,String[] args,boolean selling){
  ArrayList<Stockable> stock=npc.getTrader().getStockables(selling);
  int page=0;
  int startPoint=0;
  int numPages=stock.size() / 4;
  if (numPages == 0)   numPages=1;
  String keyword="String_Node_Str";
  if (selling)   keyword="String_Node_Str";
 else   keyword="String_Node_Str";
  if (stock.size() == 0) {
    player.sendMessage(ChatColor.GRAY + "String_Node_Str" + keyword.toLowerCase()+ "String_Node_Str");
    return;
  }
  if (stock.size() > 4 && args.length == 3) {
    page=Integer.parseInt(args[2]);
    startPoint=(4 * page) - 1;
  }
  if (startPoint > stock.size() - 1) {
    player.sendMessage(ChatColor.RED + "String_Node_Str" + StringUtils.yellowify(numPages,ChatColor.RED)+ "String_Node_Str");
    return;
  }
  player.sendMessage(ChatColor.GOLD + "String_Node_Str" + keyword+ "String_Node_Str"+ StringUtils.yellowify((page == 0 ? 1 : page),ChatColor.GOLD)+ "String_Node_Str"+ StringUtils.yellowify(numPages,ChatColor.GOLD)+ "String_Node_Str");
  player.sendMessage(ChatColor.AQUA + "String_Node_Str");
  for (int i=startPoint; i != startPoint + 3; ++i) {
    if ((stock.size() - 1) >= i) {
      Stockable s=stock.get(i);
      if (selling)       player.sendMessage(ChatColor.GREEN + keyword + "String_Node_Str"+ MessageUtils.getReverseStockableMessage(s,ChatColor.GREEN)+ "String_Node_Str");
 else       player.sendMessage(ChatColor.GREEN + keyword + "String_Node_Str"+ MessageUtils.getStockableMessage(s,ChatColor.GREEN)+ "String_Node_Str");
    }
 else {
      player.sendMessage(ChatColor.AQUA + "String_Node_Str");
      break;
    }
  }
}