Program: 42037
Project: 42037
Buggy source:
public boolean execute(ICommandSender sender,String[] args) throws Exception {
  if (args.length > 1) {
    throw new BadUsageException(getUsage());
  }
  IPlayer player=(IPlayer)sender;
  if (player.hasPermission(PermissionNames.ADMIN_PROTECT) || player.hasPermission(PermissionNames.USER_PROTECT)) {
    IWorld world=player.getWorld();
    PlotMapInfo pmi=manager.getMap(world);
    if (manager.isPlotWorld(world)) {
      PlotId id=manager.getPlotId(player);
      if (id == null) {
        player.sendMessage(C("String_Node_Str"));
        return true;
      }
 else       if (!manager.isPlotAvailable(id,world)) {
        Plot plot=manager.getPlotById(id,world);
        String name=player.getName();
        if (player.getUniqueId().equals(plot.getOwnerId()) || player.hasPermission(PermissionNames.ADMIN_PROTECT)) {
          PlotProtectChangeEvent event;
          if (plot.isProtected()) {
            event=new PlotProtectChangeEvent(world,plot,player,false);
            plugin.getEventBus().post(event);
            if (!event.isCancelled()) {
              plot.setProtected(false);
              manager.adjustWall(player);
              plugin.getSqlManager().savePlot(plot);
              player.sendMessage(C("String_Node_Str"));
              if (isAdvancedLogging()) {
                serverBridge.getLogger().info(name + "String_Node_Str" + C("String_Node_Str")+ "String_Node_Str"+ id);
              }
            }
          }
 else {
            double cost=pmi.getProtectPrice();
            if (manager.isEconomyEnabled(pmi)) {
              if (serverBridge.has(player,cost)) {
                player.sendMessage(C("String_Node_Str"));
                return true;
              }
 else {
                event=new PlotProtectChangeEvent(world,plot,player,true);
                plugin.getEventBus().post(event);
                if (!event.isCancelled()) {
                  EconomyResponse er=serverBridge.withdrawPlayer(player,cost);
                  if (!er.transactionSuccess()) {
                    player.sendMessage(er.errorMessage);
                    serverBridge.getLogger().warning(er.errorMessage);
                    return true;
                  }
                }
 else {
                  return true;
                }
              }
            }
 else {
              event=new PlotProtectChangeEvent(world,plot,player,true);
              plugin.getEventBus().post(event);
            }
            if (!event.isCancelled()) {
              plot.setProtected(true);
              manager.adjustWall(player);
              plugin.getSqlManager().savePlot(plot);
              player.sendMessage(C("String_Node_Str") + "String_Node_Str" + serverBridge.getEconomy().get().format(cost));
              if (isAdvancedLogging()) {
                serverBridge.getLogger().info(name + "String_Node_Str" + C("String_Node_Str")+ "String_Node_Str"+ id);
              }
            }
          }
        }
 else {
          player.sendMessage(C("String_Node_Str"));
        }
      }
 else {
        player.sendMessage(C("String_Node_Str") + "String_Node_Str" + id+ "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 > 1) {
    throw new BadUsageException(getUsage());
  }
  IPlayer player=(IPlayer)sender;
  if (player.hasPermission(PermissionNames.ADMIN_PROTECT) || player.hasPermission(PermissionNames.USER_PROTECT)) {
    IWorld world=player.getWorld();
    PlotMapInfo pmi=manager.getMap(world);
    if (manager.isPlotWorld(world)) {
      PlotId id=manager.getPlotId(player);
      if (id == null) {
        player.sendMessage(C("String_Node_Str"));
        return true;
      }
 else       if (!manager.isPlotAvailable(id,world)) {
        Plot plot=manager.getPlotById(id,world);
        String name=player.getName();
        if (player.getUniqueId().equals(plot.getOwnerId()) || player.hasPermission(PermissionNames.ADMIN_PROTECT)) {
          PlotProtectChangeEvent event;
          if (plot.isProtected()) {
            event=new PlotProtectChangeEvent(world,plot,player,false);
            plugin.getEventBus().post(event);
            if (!event.isCancelled()) {
              plot.setProtected(false);
              manager.adjustWall(player);
              plugin.getSqlManager().savePlot(plot);
              player.sendMessage(C("String_Node_Str"));
              if (isAdvancedLogging()) {
                serverBridge.getLogger().info(name + "String_Node_Str" + C("String_Node_Str")+ "String_Node_Str"+ id);
              }
            }
          }
 else {
            double cost=pmi.getProtectPrice();
            if (manager.isEconomyEnabled(pmi)) {
              if (serverBridge.has(player,cost)) {
                player.sendMessage(C("String_Node_Str"));
                return true;
              }
 else {
                event=new PlotProtectChangeEvent(world,plot,player,true);
                plugin.getEventBus().post(event);
                if (!event.isCancelled()) {
                  EconomyResponse er=serverBridge.withdrawPlayer(player,cost);
                  if (!er.transactionSuccess()) {
                    player.sendMessage(er.errorMessage);
                    serverBridge.getLogger().warning(er.errorMessage);
                    return true;
                  }
                }
 else {
                  return true;
                }
              }
            }
 else {
              event=new PlotProtectChangeEvent(world,plot,player,true);
              plugin.getEventBus().post(event);
            }
            if (!event.isCancelled()) {
              plot.setProtected(true);
              manager.adjustWall(player);
              plugin.getSqlManager().savePlot(plot);
              player.sendMessage(C("String_Node_Str"));
              if (isAdvancedLogging()) {
                serverBridge.getLogger().info(name + "String_Node_Str" + C("String_Node_Str")+ "String_Node_Str"+ id);
              }
            }
          }
        }
 else {
          player.sendMessage(C("String_Node_Str"));
        }
      }
 else {
        player.sendMessage(C("String_Node_Str") + "String_Node_Str" + id+ "String_Node_Str"+ C("String_Node_Str"));
      }
    }
 else {
      player.sendMessage(C("String_Node_Str"));
      return true;
    }
  }
 else {
    return false;
  }
  return true;
}