@RequestMapping("/saveCandidate")
        public String saveCandidate(Model model,
                @ModelAttribute("candidateFromRequest") Candidate candidateFromRequest,
                @ModelAttribute("skillsIdList") Set<Skill> skills,
                @ModelAttribute("vacanciesForCandidate") Set<Vacancy> vacanciesForCandidate)

<form action="saveCandidate"  id="formId" method="POST">
....
<input type="submit" value="save changes"/>
</form>

    @ModelAttribute("candidateFromRequest") Candidate candidateFromRequest

@ModelAttribute(value = "candidateFromRequest")
	public Candidate loadCandidateById(@RequestParam(required = false) Integer idCandidate) {
		if (idCandidate!= null)
			return candidateService.findById(idCandidate);
		return null;
	}