Cannot convert value of type 'com.mart.application.model.Login' to required type 'java.lang.String':

[adkri Prasanna]

@RequestMapping(value="/processLogin", method=RequestMethod.POST)
public ModelAndView processLogin(@RequestParam String phoneNoOrEmailId, @RequestParam String password, RedirectAttributes redirectAttributes) {
		Login login = loginDAO.getLoginUser(phoneNoOrEmailId, password);
		if(login != null) {
			ModelAndView modelAndView = new ModelAndView("redirect:user");
			modelAndView.addObject("sessionUserData", login);
			return modelAndView;
		}
		else {
			ModelAndView modelAndView = new ModelAndView("redirect:login");
			redirectAttributes.addFlashAttribute("errorMessage", "Invalid user credentials...");
			return modelAndView;
		}	
	}

I am trying to start a session after login. If not successfull then it will throw flash message.
Everything is fine incase of invalid login.
But successfull login throws error:
Cannot convert value of type 'com.mart.application.model.Login' to required type 'java.lang.String': no matching editors or conversion strategy found

I tried by sending text as session value hard coding. This time page loads but without session variable.
Can you please help me. I'm trying to shift from php to Java

[Himai Minh]

I guess the correct way to use ModelAndView is:
ModelAndView mav = new ModelAndView();
mav.addObject(...)
mav.setViewName("login")
return mav;

Examples can be found here  https://zetcode.com/springboot/model/ ,
https://github.com/eugenp/tutorials/blob/master/spring-web-modules/spring-mvc-basics-4/src/main/java/com/baeldung/controller/controller/PassParametersController.java
https://www.baeldung.com/spring-mvc-model-model-map-model-view