How to parse backlog issues to Java class?

Hi I am making a request to /rest/agile/latest/board/{boardId}/backlog and response has a lot of customfields and I am not sure they are exactly same for every board in our company jira. I want to parse response to java classes and I am using both java-client and jira-rest-api with feign. I could not see any method in java-client to get backlog issues. So I think I should use rest-api. Which class from package should I use with feign?
I have used with Issue class but it did not helped.

    List<Issue> getBacklogIssues(
            @PathVariable("boardId") Integer boardId,
            @RequestParam(required = false, name = "startAt") Integer startAt,
            @RequestParam(required = false, name = "maxResults") Integer maxResults