Input type=“date” thymeleaf

I need to add date to my entity and let the user set it in web form. This field needs to have today's date filled in by default.

1. <input type="date" value="2016-08-01">

shows correct date setted for default

2. <input type="date" th:value="${startDate}">

shows date picker without any value (note: String startDate = "2016-08-01";)

3. <input type="date" th:field="${startDate}">

generates 400 error (Bad request) (note: Date startDate = new Date();)

So, question is: how to use thymeleaf for input date?

can I use Date() datatype for input and store such data?
how I need to set "th:field" in form?
how I need to set "th:value" in same form?

My controller(s):

@RequestMapping("/project_new")
public String createProject(Model model) {
    Project project = new Project ();
    List<Role> roles = mRoleService.findAll();

    project.setStart(new Date());

    model.addAttribute("page_title", "create project");
    model.addAttribute("roles", roles);
    model.addAttribute("statuses", Status.values());
    model.addAttribute("project", project);
    return "project_new";
}

@RequestMapping(value = "/project_new", method = RequestMethod.POST)
public String createProject(@ModelAttribute Project project, Model model) {
    // Fill id field for project.rolesNeeded
    mRoleService.setRolesId(project.getRolesNeeded());
    project.fixCollaboratorsAndRoles();

    mProjectService.save(project);
    return "redirect:/";
}

My template:

<form th:action="@{/project_new}" method="post" th:object="${project}">
  <div class="project-list single">
    <label for="name">Name:</label>
    <input type="text" id="name" required="true" th:placeholder="*{name}" th:value="*{name}" th:field="*{name}"/>
    <label for="description">Description:</label>
    <textarea rows="5" id="description" type="text"  required="true" th:placeholder="*{description}" th:value="*{description}" th:field="*{description}"/>

    <label for="date-started">Date started:</label>
    <input type="date" th:value="${project.start}" th:field="${project.start}" id="date-started"/>

    <div>
      <label for="project_status">Project Status:</label>
      <div class="custom-select">
        <span class="dropdown-arrow"></span>
        <select th:field="*{status}" id="project_status">
          <option th:each="s : ${statuses}" th:value="${s}" th:text="${s}">Active</option>
        </select>
      </div>
    </div>

  <div class="roles-collaborators">
    <ul class="checkbox-list">
      <li th:if="${role.name} ne 'Undefined'" th:each="role : ${roles}">
      <input type="checkbox"  th:value="${role}" th:field="${project.rolesNeeded}" class="checkbox"/>
      <span th:text="${role.name}" th:value="${role}" class="checkbox">Developer</span>
      </li>
    </ul>
  </div>

  <div class="actions">
    <button type="submit" class="button">Save</button>
    <a th:href="@{/}" class="button button-secondary">Cancel</a>
  </div>
</div>
</form>

Project entity:

@Entity
public class Project {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;

@NotNull
@Size (min = 3)
private String name;

@Column(columnDefinition="TEXT")
private String description;

@Column
private Status status;

@Column
private Date start;

@ManyToMany
@LazyCollection(LazyCollectionOption.FALSE)
private List<Role> rolesNeeded;

@ManyToMany
@LazyCollection(LazyCollectionOption.FALSE)
private List<Collaborator> collaborators;

public Date getStart() {
    return start;
}

public void setStart(Date start) {
    this.start = start;
}

Taking a look at the comment with the error log it seems to be a conversion problem between String to java.util.Date. After searching for a while in the Thymeleaf GitHub I saw two issues which can explain how to proceed in this case:

Discussion of the conversion including date in this issue.
Implementacion of the conversion is explained here.

From the last point, I added an annotation to the start date of your project class:

// This is "org.springframework.format.annotation.DateTimeFormat"
@DateTimeFormat(pattern = "yyyy-MM-dd")
private Date start;

And after that, I was able to receive the date in your controller POST method.

Take into account you also need to change your "th:value" and "th:field" attributes from your template for the date value from ${project.start} to *{start} as I wrote in the comments as you did for the name and description fields.