Program: 41988
Project: 41988
Buggy source:
public boolean execute(ICommandSender sender,String[] args) throws Exception {
  if (args.length < 2 && args.length >= 3) {
    throw new BadUsageException(getUsage());
  }
  if (args[1].length() > 16 || !validUserPattern.matcher(args[1]).matches()) {
    throw new IllegalArgumentException(C("String_Node_Str"));
  }
  if ("String_Node_Str".equalsIgnoreCase(args[1]) && plugin.getConfig().getBoolean("String_Node_Str")) {
    sender.sendMessage("String_Node_Str");
    return true;
  }
  IPlayer player=(IPlayer)sender;
  if (player.hasPermission(PermissionNames.ADMIN_ADD) || player.hasPermission(PermissionNames.USER_ADD)) {
    IWorld world=player.getWorld();
    if (manager.isPlotWorld(player)) {
      PlotMapInfo pmi=manager.getMap(world);
      Plot plot=manager.getPlot(player);
      if (plot != null) {
        IOfflinePlayer allowed=resolvePlayerByName(args[1]);
        if (player.getUniqueId().equals(plot.getOwnerId()) || player.hasPermission(PermissionNames.ADMIN_ADD)) {
          if (plot.isAllowedConsulting(allowed.getUniqueId())) {
            player.sendMessage(C("String_Node_Str") + "String_Node_Str" + allowed+ "String_Node_Str"+ C("String_Node_Str"));
          }
 else {
            PlotAddAllowedEvent event=new PlotAddAllowedEvent(world,plot,player,allowed);
            serverBridge.getEventBus().post(event);
            double price=0.0;
            if (manager.isEconomyEnabled(pmi)) {
              price=pmi.getAddPlayerPrice();
              if (serverBridge.has(player,pmi.getAddPlayerPrice())) {
                player.sendMessage("String_Node_Str" + serverBridge.getEconomy().get().format(price) + "String_Node_Str"+ "String_Node_Str");
                return true;
              }
 else               if (!event.isCancelled()) {
                EconomyResponse er=serverBridge.withdrawPlayer(player,price);
                if (!er.transactionSuccess()) {
                  player.sendMessage(er.errorMessage);
                  serverBridge.getLogger().warning(er.errorMessage);
                  return true;
                }
              }
            }
            if (!event.isCancelled()) {
              IPlayer allowed2=plugin.getServerBridge().getPlayer(allowed);
              if (allowed2 != null) {
                plot.addAllowed(allowed2.getUniqueId().toString());
                plot.removeDenied(allowed2.getUniqueId().toString());
              }
 else {
                plot.addAllowed(allowed);
                plot.removeDenied(allowed);
              }
              player.sendMessage(C("String_Node_Str") + "String_Node_Str" + allowed+ "String_Node_Str"+ C("String_Node_Str"));
              if (isAdvancedLogging()) {
                if (price == 0) {
                  serverBridge.getLogger().info(player.getName() + "String_Node_Str" + C("String_Node_Str")+ "String_Node_Str"+ allowed+ "String_Node_Str"+ C("String_Node_Str")+ "String_Node_Str"+ plot.getId());
                }
 else {
                  serverBridge.getLogger().info(player.getName() + "String_Node_Str" + C("String_Node_Str")+ "String_Node_Str"+ allowed+ "String_Node_Str"+ C("String_Node_Str")+ "String_Node_Str"+ plot.getId()+ ("String_Node_Str" + C("String_Node_Str") + "String_Node_Str"+ price));
                }
              }
            }
          }
        }
 else {
          player.sendMessage(C("String_Node_Str") + "String_Node_Str" + plot.getId()+ "String_Node_Str"+ C("String_Node_Str"));
        }
      }
 else {
        player.sendMessage(C("String_Node_Str") + "String_Node_Str" + plot.getId()+ "String_Node_Str"+ C("String_Node_Str"));
      }
    }
 else {
      player.sendMessage(C("String_Node_Str"));
      return true;
    }
  }
 else {
    return false;
  }
  return true;
}

Fixed version (ground truth):
public boolean execute(ICommandSender sender,String[] args) throws Exception {
  if (args.length < 2 && args.length >= 3) {
    throw new BadUsageException(getUsage());
  }
  if (args[1].length() > 16 || !validUserPattern.matcher(args[1]).matches()) {
    throw new IllegalArgumentException(C("String_Node_Str"));
  }
  if ("String_Node_Str".equals(args[1]) && plugin.getConfig().getBoolean("String_Node_Str")) {
    sender.sendMessage("String_Node_Str");
    return true;
  }
  IPlayer player=(IPlayer)sender;
  if (player.hasPermission(PermissionNames.ADMIN_ADD) || player.hasPermission(PermissionNames.USER_ADD)) {
    IWorld world=player.getWorld();
    if (manager.isPlotWorld(player)) {
      PlotMapInfo pmi=manager.getMap(world);
      Plot plot=manager.getPlot(player);
      if (plot != null) {
        IOfflinePlayer allowed=resolvePlayerByName(args[1]);
        if (player.getUniqueId().equals(plot.getOwnerId()) || player.hasPermission(PermissionNames.ADMIN_ADD)) {
          if (plot.isAllowedConsulting(allowed.getUniqueId())) {
            player.sendMessage(C("String_Node_Str") + "String_Node_Str" + allowed+ "String_Node_Str"+ C("String_Node_Str"));
          }
 else {
            PlotAddAllowedEvent event=new PlotAddAllowedEvent(world,plot,player,allowed);
            serverBridge.getEventBus().post(event);
            double price=0.0;
            if (manager.isEconomyEnabled(pmi)) {
              price=pmi.getAddPlayerPrice();
              if (serverBridge.has(player,pmi.getAddPlayerPrice())) {
                player.sendMessage("String_Node_Str" + serverBridge.getEconomy().get().format(price) + "String_Node_Str"+ "String_Node_Str");
                return true;
              }
 else               if (!event.isCancelled()) {
                EconomyResponse er=serverBridge.withdrawPlayer(player,price);
                if (!er.transactionSuccess()) {
                  player.sendMessage(er.errorMessage);
                  serverBridge.getLogger().warning(er.errorMessage);
                  return true;
                }
              }
            }
            if (!event.isCancelled()) {
              IPlayer allowed2=plugin.getServerBridge().getPlayer(allowed);
              if (allowed2 != null) {
                plot.addAllowed(allowed2.getUniqueId().toString());
                plot.removeDenied(allowed2.getUniqueId().toString());
              }
 else {
                plot.addAllowed(allowed);
                plot.removeDenied(allowed);
              }
              player.sendMessage(C("String_Node_Str") + "String_Node_Str" + allowed+ "String_Node_Str"+ C("String_Node_Str"));
              if (isAdvancedLogging()) {
                if (price == 0) {
                  serverBridge.getLogger().info(player.getName() + "String_Node_Str" + C("String_Node_Str")+ "String_Node_Str"+ allowed+ "String_Node_Str"+ C("String_Node_Str")+ "String_Node_Str"+ plot.getId());
                }
 else {
                  serverBridge.getLogger().info(player.getName() + "String_Node_Str" + C("String_Node_Str")+ "String_Node_Str"+ allowed+ "String_Node_Str"+ C("String_Node_Str")+ "String_Node_Str"+ plot.getId()+ ("String_Node_Str" + C("String_Node_Str") + "String_Node_Str"+ price));
                }
              }
            }
          }
        }
 else {
          player.sendMessage(C("String_Node_Str") + "String_Node_Str" + plot.getId()+ "String_Node_Str"+ C("String_Node_Str"));
        }
      }
 else {
        player.sendMessage(C("String_Node_Str") + "String_Node_Str" + plot.getId()+ "String_Node_Str"+ C("String_Node_Str"));
      }
    }
 else {
      player.sendMessage(C("String_Node_Str"));
      return true;
    }
  }
 else {
    return false;
  }
  return true;
}