Neither BindingResult nor plain target object for bean name 'userProfile' available as request attribute

Question

I've encountered the folowing exception while I was trying to implement my first spring+hibernate web app:

java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'userProfile' available as request attribute
    at org.springframework.web.servlet.support.BindStatus.<init>(BindStatus.java:141)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getBindStatus(AbstractDataBoundFormElementTag.java:174)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getPropertyPath(AbstractDataBoundFormElementTag.java:194)
    at org.springframework.web.servlet.tags.form.LabelTag.autogenerateFor(LabelTag.java:129)
    ...

UserController.java:

@Controller
public class UserController {

    @Autowired
    private UserProfileService userProfileService;

    public UserController(){

    }

    @RequestMapping(value="/add", method=RequestMethod.POST)
    public String registerUser(@ModelAttribute("userProfile") UserProfile userProfile, BindingResult result, Map model){

        userProfileService.addUserProfile(userProfile);

        return "redirect:/login";
    }
    ...
}

UserProfile.java

@Entity
@Table(name="USER_PROFILE")
public class UserProfile {
    @Id
    @GeneratedValue
    @Column(name = "ID")
    private Long id;

    @Column(name = "USERNAME")
    private String userName;

    @Column(name = "PASSWORD")
    private String password;

    //sets and gets
}

index.jsp

<form:form method="post" action="add" commandName="userProfile">
    <table>
        <tr>
            <td><form:label path="userName"><spring:message code="label.username" /></form:label></td>
            <td><form:input path="userName" /></td>
        </tr>
        <tr>
            <td><form:label path="password"><spring:message code="label.password" /></form:label></td>
            <td><form:password path="password" /></td>
        </tr>
        <tr>
            <td><input type="submit" value="<spring:message code="label.adduser" />"></td>
        </tr>
    </table>
</form:form>

Solution 1

I wasn't noticed that I have to implement method for form creation which will provide instance of UserProfile. I've added 2 methods and now everything works fine.

@RequestMapping("/")
public String home() {
    return "redirect:/index";
}

@RequestMapping(value = "/index", method = RequestMethod.GET)
public String createRegisterForm(Map<String, Object> model){
    model.put("userprofile", new UserProfile());
    return "index";
}

Solution 2

Add modelAttribute="userProfile" to the <form:form> tag.

<form:form method="post" action="add" commandName="userProfile" modelAttribute="userProfile">