#vulnerable code 
                                public static Result createArea(String areaName) {
        // prevent too many areas
        if(AREAS.size() > (MAX -1)) {
            return new Result(false, "KV_AREA_CREATE_ERROR");
        }
        if(StringUtils.isBlank(areaName)) {
            return Result.getFailed(ErrorCode.NULL_PARAMETER);
        }
        if (AREAS.containsKey(areaName)) {
            return new Result(true, "KV_AREA_EXISTS");
        }
        //TODO 特殊字符校验
        if(!checkPathLegal(areaName)) {
            return new Result(false, "KV_AREA_CREATE_ERROR");
        }
        Result result;
        try {
            File dir = new File(dataPath + File.separator + areaName);
            if(!dir.exists()) {
                dir.mkdir();
            }
            String filePath = dataPath + File.separator + areaName + File.separator + BASE_DB_NAME;
            DB db = openDB(filePath, true);
            AREAS.put(areaName, db);
            result = Result.getSuccess();
        } catch (Exception e) {
            Log.error("error create area: " + areaName, e);
            result = new Result(false, "KV_AREA_CREATE_ERROR");
        }
        return result;
    } 
                            #location 7 
                            #vulnerability type THREAD_SAFETY_VIOLATION
#fixed code
                                public static Result createArea(String areaName) {
        // prevent too many areas
        if(AREAS.size() > (MAX -1)) {
            return new Result(false, "KV_AREA_CREATE_ERROR");
        }
        if(StringUtils.isBlank(areaName)) {
            return Result.getFailed(ErrorCode.NULL_PARAMETER);
        }
        if (AREAS.containsKey(areaName)) {
            return new Result(true, "KV_AREA_EXISTS");
        }
        if(!checkPathLegal(areaName)) {
            return new Result(false, "KV_AREA_CREATE_ERROR");
        }
        Result result;
        try {
            File dir = new File(dataPath + File.separator + areaName);
            if(!dir.exists()) {
                dir.mkdir();
            }
            String filePath = dataPath + File.separator + areaName + File.separator + BASE_DB_NAME;
            DB db = openDB(filePath, true);
            AREAS.put(areaName, db);
            result = Result.getSuccess();
        } catch (Exception e) {
            Log.error("error create area: " + areaName, e);
            result = new Result(false, "KV_AREA_CREATE_ERROR");
        }
        return result;
    }