Program: 51681
Project: 51681
Buggy source:
public void secureMode(InventoryClickEvent event,TraderStatus trader,StockItem si,InventoryTrait sr){
  if (event.getWhoClicked() instanceof Player) {
    Player p=(Player)event.getWhoClicked();
    DecimalFormat f=new DecimalFormat("String_Node_Str");
    if (trader.getStatus().equals(Status.PLAYER_SELL) || trader.getStatus().equals(Status.PLAYER_SELL_AMOUT)) {
      if (trader.getStatus().equals(Status.PLAYER_SELL_AMOUT))       si=trader.getStockItem();
 else       si=sr.itemForSell(event.getSlot());
      if (si != null) {
        if (event.isShiftClick()) {
          if (si.hasMultipleAmouts() && trader.getStatus().equals(Status.PLAYER_SELL_AMOUT)) {
            if (econ.has(p.getName(),si.getPrice(event.getSlot()))) {
              if (!event.getCurrentItem().equals(new ItemStack(Material.WOOL,1,(short)0,(byte)14)) && !event.getCurrentItem().getType().equals(Material.AIR)) {
                econ.withdrawPlayer(p.getName(),si.getPrice(event.getSlot()));
                p.getInventory().addItem(event.getCurrentItem());
                p.sendMessage(ChatColor.GOLD + "String_Node_Str" + event.getCurrentItem().getAmount()+ "String_Node_Str"+ f.format(si.getPrice(event.getSlot()))+ "String_Node_Str");
              }
            }
 else {
              p.sendMessage(ChatColor.GOLD + "String_Node_Str");
            }
          }
 else {
            if (econ.has(p.getName(),si.getPrice())) {
              econ.withdrawPlayer(p.getName(),si.getPrice());
              p.getInventory().addItem(si.getItemStack());
              p.sendMessage(ChatColor.GOLD + "String_Node_Str" + si.getItemStack().getAmount()+ "String_Node_Str"+ f.format(si.getPrice())+ "String_Node_Str");
            }
 else {
              p.sendMessage(ChatColor.GOLD + "String_Node_Str");
            }
          }
        }
 else {
          if (trader.getStatus().equals(Status.PLAYER_SELL_AMOUT)) {
            if (event.getCurrentItem().equals(new ItemStack(Material.WOOL,1,(short)0,(byte)14)) && (event.getSlot() == trader.getInventory().getSize() - 1)) {
              trader.getInventory().clear();
              sr.inventoryView(trader.getInventory(),Status.PLAYER_SELL);
              trader.setStatus(Status.PLAYER_SELL);
              trader.setStockItem(null);
            }
 else {
              if (!event.getCurrentItem().equals(new ItemStack(Material.WOOL,1,(short)0,(byte)14)) && !event.getCurrentItem().getType().equals(Material.AIR))               p.sendMessage(ChatColor.GOLD + "String_Node_Str" + f.format(si.getPrice(event.getSlot()))+ "String_Node_Str");
            }
          }
 else           if (trader.getStatus().equals(Status.PLAYER_SELL)) {
            if (si.hasMultipleAmouts()) {
              if (trader.getStatus().equals(Status.PLAYER_SELL)) {
                trader.getInventory().clear();
                InventoryTrait.setInventoryWith(trader.getInventory(),si);
                trader.setStatus(Status.PLAYER_SELL_AMOUT);
                trader.setStockItem(si);
              }
            }
 else {
              p.sendMessage(ChatColor.GOLD + "String_Node_Str" + f.format(si.getPrice())+ "String_Node_Str");
            }
          }
        }
      }
 else       if (event.getCurrentItem().equals(new ItemStack(Material.WOOL,1,(short)0,(byte)5)) && (event.getSlot() == trader.getInventory().getSize() - 1)) {
        trader.getInventory().clear();
        sr.inventoryView(trader.getInventory(),Status.PLAYER_BUY);
        trader.setStatus(Status.PLAYER_BUY);
        trader.setStockItem(null);
      }
    }
 else     if (trader.getStatus().equals(Status.PLAYER_BUY)) {
      si=sr.wantItemBuy(event.getSlot());
      if (si != null) {
        if (si.getItemStack().getType().equals(event.getCursor().getType()) && si.getItemStack().getData().equals(event.getCursor().getData())) {
          econ.depositPlayer(p.getName(),si.getPrice() * event.getCursor().getAmount());
          p.sendMessage(ChatColor.GOLD + "String_Node_Str" + event.getCursor().getAmount()+ "String_Node_Str"+ f.format(si.getPrice() * event.getCursor().getAmount())+ "String_Node_Str");
          event.setCursor(new ItemStack(Material.AIR));
        }
 else {
          if (!event.getCurrentItem().equals(new ItemStack(Material.WOOL,1,(short)0,(byte)3)) && !event.getCurrentItem().getType().equals(Material.AIR))           p.sendMessage(ChatColor.GOLD + "String_Node_Str" + f.format(si.getPrice())+ "String_Node_Str");
        }
      }
 else {
        if (event.getCurrentItem().equals(new ItemStack(Material.WOOL,1,(short)0,(byte)3)) && (event.getSlot() == trader.getInventory().getSize() - 1)) {
          trader.getInventory().clear();
          sr.inventoryView(trader.getInventory(),Status.PLAYER_SELL);
          trader.setStatus(Status.PLAYER_SELL);
          trader.setStockItem(null);
        }
      }
    }
  }
}

Fixed version (ground truth):
public void secureMode(InventoryClickEvent event,TraderStatus trader,StockItem si,InventoryTrait sr){
  if (event.getWhoClicked() instanceof Player) {
    Player p=(Player)event.getWhoClicked();
    DecimalFormat f=new DecimalFormat("String_Node_Str");
    boolean top=event.getView().convertSlot(event.getRawSlot()) == event.getRawSlot();
    if (trader.getStatus().equals(Status.PLAYER_SELL) || trader.getStatus().equals(Status.PLAYER_SELL_AMOUT) && top) {
      if (trader.getStatus().equals(Status.PLAYER_SELL_AMOUT))       si=trader.getStockItem();
 else       si=sr.itemForSell(event.getSlot());
      if (si != null) {
        if (event.isShiftClick()) {
          if (si.hasMultipleAmouts() && trader.getStatus().equals(Status.PLAYER_SELL_AMOUT)) {
            if (econ.has(p.getName(),si.getPrice(event.getSlot()))) {
              if (!event.getCurrentItem().equals(new ItemStack(Material.WOOL,1,(short)0,(byte)14)) && !event.getCurrentItem().getType().equals(Material.AIR)) {
                econ.withdrawPlayer(p.getName(),si.getPrice(event.getSlot()));
                p.getInventory().addItem(event.getCurrentItem());
                p.sendMessage(ChatColor.GOLD + "String_Node_Str" + event.getCurrentItem().getAmount()+ "String_Node_Str"+ f.format(si.getPrice(event.getSlot()))+ "String_Node_Str");
              }
            }
 else {
              p.sendMessage(ChatColor.GOLD + "String_Node_Str");
            }
          }
 else {
            if (econ.has(p.getName(),si.getPrice())) {
              econ.withdrawPlayer(p.getName(),si.getPrice());
              p.getInventory().addItem(si.getItemStack());
              p.sendMessage(ChatColor.GOLD + "String_Node_Str" + si.getItemStack().getAmount()+ "String_Node_Str"+ f.format(si.getPrice())+ "String_Node_Str");
            }
 else {
              p.sendMessage(ChatColor.GOLD + "String_Node_Str");
            }
          }
        }
 else {
          if (trader.getStatus().equals(Status.PLAYER_SELL_AMOUT)) {
            if (event.getCurrentItem().equals(new ItemStack(Material.WOOL,1,(short)0,(byte)14)) && (event.getSlot() == trader.getInventory().getSize() - 1)) {
              trader.getInventory().clear();
              sr.inventoryView(trader.getInventory(),Status.PLAYER_SELL);
              trader.setStatus(Status.PLAYER_SELL);
              trader.setStockItem(null);
            }
 else {
              if (!event.getCurrentItem().equals(new ItemStack(Material.WOOL,1,(short)0,(byte)14)) && !event.getCurrentItem().getType().equals(Material.AIR))               p.sendMessage(ChatColor.GOLD + "String_Node_Str" + f.format(si.getPrice(event.getSlot()))+ "String_Node_Str");
            }
          }
 else           if (trader.getStatus().equals(Status.PLAYER_SELL)) {
            if (si.hasMultipleAmouts()) {
              if (trader.getStatus().equals(Status.PLAYER_SELL)) {
                trader.getInventory().clear();
                InventoryTrait.setInventoryWith(trader.getInventory(),si);
                trader.setStatus(Status.PLAYER_SELL_AMOUT);
                trader.setStockItem(si);
              }
            }
 else {
              p.sendMessage(ChatColor.GOLD + "String_Node_Str" + f.format(si.getPrice())+ "String_Node_Str");
            }
          }
        }
      }
 else       if (event.getCurrentItem().equals(new ItemStack(Material.WOOL,1,(short)0,(byte)5)) && (event.getSlot() == trader.getInventory().getSize() - 1)) {
        trader.getInventory().clear();
        sr.inventoryView(trader.getInventory(),Status.PLAYER_BUY);
        trader.setStatus(Status.PLAYER_BUY);
        trader.setStockItem(null);
      }
      event.setCancelled(true);
    }
 else     if (trader.getStatus().equals(Status.PLAYER_BUY) && top) {
      si=sr.wantItemBuy(event.getSlot());
      if (si != null) {
        if (si.getItemStack().getType().equals(event.getCursor().getType()) && si.getItemStack().getData().equals(event.getCursor().getData())) {
          econ.depositPlayer(p.getName(),si.getPrice() * event.getCursor().getAmount());
          p.sendMessage(ChatColor.GOLD + "String_Node_Str" + event.getCursor().getAmount()+ "String_Node_Str"+ f.format(si.getPrice() * event.getCursor().getAmount())+ "String_Node_Str");
          event.setCursor(new ItemStack(Material.AIR));
        }
 else {
          if (!event.getCurrentItem().equals(new ItemStack(Material.WOOL,1,(short)0,(byte)3)) && !event.getCurrentItem().getType().equals(Material.AIR))           p.sendMessage(ChatColor.GOLD + "String_Node_Str" + f.format(si.getPrice())+ "String_Node_Str");
        }
      }
 else {
        if (event.getCurrentItem().equals(new ItemStack(Material.WOOL,1,(short)0,(byte)3)) && (event.getSlot() == trader.getInventory().getSize() - 1)) {
          trader.getInventory().clear();
          sr.inventoryView(trader.getInventory(),Status.PLAYER_SELL);
          trader.setStatus(Status.PLAYER_SELL);
          trader.setStockItem(null);
        }
      }
      event.setCancelled(true);
    }
  }
}