output: #fixed code
                               @Override
  	public String doImportFolder(HttpServletRequest request, MultipartFile file) {
  		final String account = (String) request.getSession().getAttribute("ACCOUNT");
  		String folderId = request.getParameter("folderId");
  		final String originalFileName = new String(file.getOriginalFilename().getBytes(Charset.forName("UTF-8")),
  				Charset.forName("UTF-8"));
  		String folderConstraint = request.getParameter("folderConstraint");
  		// 再次检查上传文件名与目标目录ID
  		if (folderId == null || folderId.length() <= 0 || originalFileName == null || originalFileName.length() <= 0) {
  			return UPLOADERROR;
  		}
  		Folder folder = flm.queryById(folderId);
  		if (folder == null) {
  			return UPLOADERROR;
  		}
  		// 检查上传权限
  		if (!ConfigureReader.instance().authorized(account, AccountAuth.UPLOAD_FILES)
  				|| !ConfigureReader.instance().accessFolder(folder, account)) {
  			return UPLOADERROR;
  		}
  		// 检查上传文件体积是否超限
  		long mufs = ConfigureReader.instance().getUploadFileSize(account);
  		if (mufs >= 0 && file.getSize() > mufs) {
  			return UPLOADERROR;
  		}
  		// 检查是否具备创建文件夹权限，若有则使用请求中提供的文件夹访问级别，否则使用默认访问级别
  		int pc = folder.getFolderConstraint();
  		if (ConfigureReader.instance().authorized(account, AccountAuth.CREATE_NEW_FOLDER)) {
  			try {
  				int ifc = Integer.parseInt(folderConstraint);
  				if (ifc > 0 && account == null) {
  					return UPLOADERROR;
  				}
  				if (ifc < pc) {
  					return UPLOADERROR;
  				}
  			} catch (Exception e) {
  				return UPLOADERROR;
  			}
  		} else {
  			folderConstraint = pc + "";
  		}
  		// 计算相对路径的文件夹ID（即真正要保存的文件夹目标）
  		String[] paths = getParentPath(originalFileName);
  		// 将当前操作的文件夹路径加入到安全锁中，确保同一时间内无法对该文件夹进行重复导入，避免发生文件冲突的问题。
  		String result = protectImportFolder(paths, folderId, account, folderConstraint, originalFileName, file);
  		return result;
  	}
input: #vulnerable code 
                               @Override
  	public String doImportFolder(HttpServletRequest request, MultipartFile file) {
  		String account = (String) request.getSession().getAttribute("ACCOUNT");
  		String folderId = request.getParameter("folderId");
  		final String originalFileName = new String(file.getOriginalFilename().getBytes(Charset.forName("UTF-8")),
  				Charset.forName("UTF-8"));
  		final String folderConstraint = request.getParameter("folderConstraint");
  		// 再次检查上传文件名与目标目录ID
  		if (folderId == null || folderId.length() <= 0 || originalFileName == null || originalFileName.length() <= 0) {
  			return UPLOADERROR;
  		}
  		Folder folder = flm.queryById(folderId);
  		if (folder == null) {
  			return UPLOADERROR;
  		}
  		// 检查上传权限
  		if (!ConfigureReader.instance().authorized(account, AccountAuth.UPLOAD_FILES)
  				|| !ConfigureReader.instance().accessFolder(folder, account)) {
  			return UPLOADERROR;
  		}
  		// 检查上传文件体积是否超限
  		long mufs = ConfigureReader.instance().getUploadFileSize(account);
  		if (mufs >= 0 && file.getSize() > mufs) {
  			return UPLOADERROR;
  		}
  		// 计算相对路径的文件夹ID（即真正要保存的文件夹目标）
  		String[] paths = getParentPath(originalFileName);
  		//将当前操作的文件夹路径加入到安全锁中，确保同一时间内无法对该文件夹进行重复导入，避免发生文件冲突的问题。
  		String pathskey = Arrays.toString(paths);
  		synchronized (pathsKeys) {
  			if(pathsKeys.contains(pathskey)) {
  				return UPLOADERROR;
  			}else {
  				pathsKeys.add(pathskey);
  			}
  		}
  		String result = protectImportFolder(paths, folderId, account, folderConstraint, originalFileName, file);
  		synchronized (pathsKeys) {
  			pathsKeys.remove(pathskey);
  		}
  		return result;
  	} 
                              #location 30 
                              #vulnerability type THREAD_SAFETY_VIOLATION