Program: 51697
Project: 51697
Buggy source:
@SuppressWarnings("String_Node_Str") @EventHandler public void inventoryClick(InventoryClickEvent event){
  if (event.getWhoClicked() instanceof Player) {
    Player p=(Player)event.getWhoClicked();
    if (state.containsKey(p.getName())) {
      TraderStatus trader=state.get(p.getName());
      InventoryTrait sr=trader.getTrader().getTrait(InventoryTrait.class);
      boolean top=event.getView().convertSlot(event.getRawSlot()) == event.getRawSlot();
      if (!trader.getStatus().equals(Status.PLAYER_MANAGE) && top) {
        StockItem si=null;
        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()) {
                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"+ 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"+ 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" + 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" + 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())) {
              econ.depositPlayer(p.getName(),si.getPrice() * event.getCursor().getAmount());
              p.sendMessage(ChatColor.GOLD + "String_Node_Str" + event.getCursor().getAmount()+ "String_Node_Str"+ si.getPrice(event.getSlot())+ "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" + si.getPrice(event.getSlot())+ "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);
      }
 else {
      }
    }
  }
}

Fixed version (ground truth):
@SuppressWarnings("String_Node_Str") @EventHandler public void inventoryClick(InventoryClickEvent event){
  if (event.getRawSlot() < 0)   return;
  if (event.getWhoClicked() instanceof Player) {
    Player p=(Player)event.getWhoClicked();
    if (state.containsKey(p.getName())) {
      TraderStatus trader=state.get(p.getName());
      InventoryTrait sr=trader.getTrader().getTrait(InventoryTrait.class);
      boolean top=event.getView().convertSlot(event.getRawSlot()) == event.getRawSlot();
      if (!trader.getStatus().equals(Status.PLAYER_MANAGE) && top) {
        StockItem si=null;
        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()) {
                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"+ 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"+ 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" + 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" + 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())) {
              econ.depositPlayer(p.getName(),si.getPrice() * event.getCursor().getAmount());
              p.sendMessage(ChatColor.GOLD + "String_Node_Str" + event.getCursor().getAmount()+ "String_Node_Str"+ si.getPrice(event.getSlot())+ "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" + si.getPrice(event.getSlot())+ "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);
      }
 else {
      }
    }
  }
}