problem description:
if the request method private ModelAndView articleList (Map < String, Object > map) adds an access control annotation @ PreAuthorize and uses private , it will report an error: java.lang.NullPointerException: null , where null refers to articleService as null. On the surface, it may be the class method permission problem caused by modifiers. Why can you access it without annotating @ PreAuthorize , but not if you add it? Please explain it in depth.

...
@Autowired
private ArticleService articleService;
...

@GetMapping("/articles")
@PreAuthorize("hasAnyAuthority("admin")")
public  ModelAndView articleList(Map<String, Object> map){
    List<ArticleDTO> articleListDTO = articleService.articleInfoList();
    map.put("articleList", articleListDTO);
    return new ModelAndView("article/article_list", map);
}