#vulnerable code 
                                @Override
    public Result exportAccount(String address, String password) {
        Account account = null;
        if (!StringUtils.isBlank(address)) {
            account = accountCacheService.getAccountByAddress(address);
            if (account == null) {
                return Result.getFailed(ErrorCode.DATA_NOT_FOUND);
            }
        }
        if (!account.decrypt(password)) {
            return Result.getFailed(ErrorCode.PASSWORD_IS_WRONG);
        }

        Result result = backUpFile("");
        if (!result.isSuccess()) {
            return result;
        }
        return exportAccount(account, (File) result.getObject());
    } 
                            #location 10 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Override
    public Result exportAccount(String address, String password) {
        Account account = null;
        if (!StringUtils.isBlank(address)) {
            account = accountCacheService.getAccountByAddress(address);
            if (account == null) {
                return Result.getFailed(ErrorCode.DATA_NOT_FOUND);
            }
            if (account.isEncrypted()) {
                if (!StringUtils.validPassword(password) || !account.decrypt(password)) {
                    return Result.getFailed(ErrorCode.PASSWORD_IS_WRONG);
                }
            }
        }

        Result result = backUpFile("");
        if (!result.isSuccess()) {
            return result;
        }
        return exportAccount(account, (File) result.getObject());
    }