Program: 1809
Project: 1809
Buggy source:
public static void instantiateQuests(ConfigurationHandler quests){
  int questCount=0;
  for (  String questName : quests.getKeys(null)) {
    String path=questName + "String_Node_Str";
    Quest quest=new Quest(questName);
    quest.setDescription(quests.getString(path + "String_Node_Str"));
    quest.setCompletedText(quests.getString(path + "String_Node_Str"));
    quest.setAcceptanceText(quests.getString(path + "String_Node_Str"));
    quest.setRepeatable(quests.getBoolean(path + "String_Node_Str"));
    String tempPath=path;
    if (quests.pathExists(path + "String_Node_Str")) {
      for (      String reward : quests.getKeys(path + "String_Node_Str")) {
        path=tempPath + "String_Node_Str" + reward+ "String_Node_Str";
        String type=quests.getString(path + "String_Node_Str");
        boolean take=quests.getBoolean(path + "String_Node_Str");
        if (type.equals("String_Node_Str")) {
          int amount=quests.getInt(path + "String_Node_Str");
          quest.addReward(new HealthReward(amount,take));
        }
 else         if (type.equals("String_Node_Str")) {
          int id=quests.getInt(path + "String_Node_Str");
          int amount=quests.getInt(path + "String_Node_Str");
          byte data=0;
          if (quests.pathExists(path + "String_Node_Str"))           data=(byte)quests.getInt(path + "String_Node_Str");
          ItemStack stack=new ItemStack(id,amount);
          stack.setData(new MaterialData(id,data));
          quest.addReward(new ItemReward(stack,take));
        }
 else         if (type.equals("String_Node_Str")) {
          double amount=quests.getDouble(path + "String_Node_Str");
          quest.addReward(new EconpluginReward(amount,take));
        }
 else         if (type.equals("String_Node_Str")) {
          String permission=quests.getString(path + "String_Node_Str");
          quest.addReward(new PermissionReward(permission,take));
        }
 else         if (type.equals("String_Node_Str")) {
          String questToGive=quests.getString(path + "String_Node_Str");
          quest.addReward(new QuestReward(questToGive));
        }
 else         if (type.equals("String_Node_Str")) {
          String rank=quests.getString(path + "String_Node_Str");
          quest.addReward(new RankReward(rank));
        }
      }
    }
    path=tempPath=questName + "String_Node_Str";
    Objectives objectives=new Objectives();
    if (quests.pathExists(path)) {
      for (      Object step : quests.getKeys(path)) {
        QuestStep tempStep=new QuestStep();
        for (        Object objective : quests.getKeys(path + "String_Node_Str" + step)) {
          path=tempPath + objective;
          QuestType type=QuestType.getType(quests.getString(path + "String_Node_Str"));
          if (type == null) {
            Messaging.log("String_Node_Str" + (questCount + 1) + "String_Node_Str");
            continue;
          }
          Objective.Builder obj=new Objective.Builder(type);
          if (quests.pathExists(path + "String_Node_Str"))           obj.amount(quests.getInt(path + "String_Node_Str"));
          if (quests.pathExists(path + "String_Node_Str"))           obj.destination(quests.getInt(path + "String_Node_Str"));
          if (quests.pathExists(path + "String_Node_Str")) {
            int id=quests.getInt(path + "String_Node_Str");
            int amount=quests.getInt(path + "String_Node_Str");
            byte data=0;
            if (quests.pathExists(path + "String_Node_Str"))             data=(byte)quests.getInt(path + "String_Node_Str");
            ItemStack stack=new ItemStack(id,amount);
            stack.setData(new MaterialData(id,data));
            obj.item(stack);
          }
          if (quests.pathExists(path + "String_Node_Str")) {
            obj.location(LocationUtils.loadLocation(quests,path,false));
          }
          if (quests.pathExists(path + "String_Node_Str")) {
            obj.message(quests.getString(path + "String_Node_Str"));
          }
          if (quests.pathExists(path + "String_Node_Str")) {
            if (quests.getInt(path + "String_Node_Str") != 0)             obj.material(Material.getMaterial(quests.getInt(path + "String_Node_Str")));
          }
          tempStep.add(obj.build());
        }
        objectives.add(tempStep);
      }
    }
    if (objectives.all().size() == 0) {
      quest=null;
      Messaging.log("String_Node_Str" + (questCount + 1) + "String_Node_Str");
      continue;
    }
    quest.setObjectives(objectives);
    QuestManager.addQuest(quest);
    ++questCount;
  }
  Messaging.log("String_Node_Str" + questCount + "String_Node_Str");
}

Fixed version (ground truth):
public static void instantiateQuests(ConfigurationHandler quests){
  int questCount=0;
  for (  String questName : quests.getKeys(null)) {
    String path=questName + "String_Node_Str";
    Quest quest=new Quest(questName);
    quest.setDescription(quests.getString(path + "String_Node_Str"));
    quest.setCompletedText(quests.getString(path + "String_Node_Str"));
    quest.setAcceptanceText(quests.getString(path + "String_Node_Str"));
    quest.setRepeatable(quests.getBoolean(path + "String_Node_Str"));
    String tempPath=path;
    if (quests.pathExists(path + "String_Node_Str")) {
      for (      String reward : quests.getKeys(path + "String_Node_Str")) {
        path=tempPath + "String_Node_Str" + reward+ "String_Node_Str";
        String type=quests.getString(path + "String_Node_Str");
        boolean take=quests.getBoolean(path + "String_Node_Str");
        if (type.equals("String_Node_Str")) {
          int amount=quests.getInt(path + "String_Node_Str");
          quest.addReward(new HealthReward(amount,take));
        }
 else         if (type.equals("String_Node_Str")) {
          int id=quests.getInt(path + "String_Node_Str");
          int amount=quests.getInt(path + "String_Node_Str");
          byte data=0;
          if (quests.pathExists(path + "String_Node_Str"))           data=(byte)quests.getInt(path + "String_Node_Str");
          ItemStack stack=new ItemStack(id,amount);
          stack.setData(new MaterialData(id,data));
          quest.addReward(new ItemReward(stack,take));
        }
 else         if (type.equals("String_Node_Str")) {
          double amount=quests.getDouble(path + "String_Node_Str");
          quest.addReward(new EconpluginReward(amount,take));
        }
 else         if (type.equals("String_Node_Str")) {
          String permission=quests.getString(path + "String_Node_Str");
          quest.addReward(new PermissionReward(permission,take));
        }
 else         if (type.equals("String_Node_Str")) {
          String questToGive=quests.getString(path + "String_Node_Str");
          quest.addReward(new QuestReward(questToGive));
        }
 else         if (type.equals("String_Node_Str")) {
          String rank=quests.getString(path + "String_Node_Str");
          quest.addReward(new RankReward(rank));
        }
      }
    }
    path=tempPath=questName + "String_Node_Str";
    Objectives objectives=new Objectives();
    if (quests.pathExists(path)) {
      for (      Object step : quests.getKeys(path)) {
        QuestStep tempStep=new QuestStep();
        tempPath=questName + "String_Node_Str" + step;
        for (        Object objective : quests.getKeys(path + "String_Node_Str" + step)) {
          path=tempPath + "String_Node_Str" + objective;
          QuestType type=QuestType.getType(quests.getString(path + "String_Node_Str"));
          if (type == null) {
            Messaging.log("String_Node_Str" + (questCount + 1) + "String_Node_Str");
            continue;
          }
          Objective.Builder obj=new Objective.Builder(type);
          if (quests.pathExists(path + "String_Node_Str"))           obj.amount(quests.getInt(path + "String_Node_Str"));
          if (quests.pathExists(path + "String_Node_Str"))           obj.destination(quests.getInt(path + "String_Node_Str"));
          if (quests.pathExists(path + "String_Node_Str")) {
            int id=quests.getInt(path + "String_Node_Str");
            int amount=quests.getInt(path + "String_Node_Str");
            byte data=0;
            if (quests.pathExists(path + "String_Node_Str"))             data=(byte)quests.getInt(path + "String_Node_Str");
            ItemStack stack=new ItemStack(id,amount);
            stack.setData(new MaterialData(id,data));
            obj.item(stack);
          }
          if (quests.pathExists(path + "String_Node_Str")) {
            obj.location(LocationUtils.loadLocation(quests,path,false));
          }
          if (quests.pathExists(path + "String_Node_Str")) {
            obj.message(quests.getString(path + "String_Node_Str"));
          }
          if (quests.pathExists(path + "String_Node_Str")) {
            if (quests.getInt(path + "String_Node_Str") != 0)             obj.material(Material.getMaterial(quests.getInt(path + "String_Node_Str")));
          }
          tempStep.add(obj.build());
        }
        objectives.add(tempStep);
      }
    }
    if (objectives.all().size() == 0) {
      quest=null;
      Messaging.log("String_Node_Str" + (questCount + 1) + "String_Node_Str");
      continue;
    }
    quest.setObjectives(objectives);
    QuestManager.addQuest(quest);
    ++questCount;
  }
  Messaging.log("String_Node_Str" + questCount + "String_Node_Str");
}