Spring Form hidden value is lost on submit - spring-mvc

Question

On my 'update user' page I have a hidden field to hold the ID of the current user being edited. I've checked the HTML source and the value populates correctly. However when I submit the form, the userID value ALWAYS comes through as 0 while every other field comes through correctly.
-I've tried setting the type as form:input and submitting it, still 0 on the controller side.
-There are no bindingresult errors.
-Page URL: /admin/update-user.html?uid=3 (I've tried changing the URL variable from uid to userID, no difference.)
So what the heck is going on?! Am I missing something obvious??
JSTL
<form:form commandName="user" method="POST">
<form:hidden path="userID"/>
<table width="400" cellpadding="3" cellspacing="0" border="0" class="datatable">
<tr>
<td>User ID #</td>
<td>${user.userID}</td>
</tr>
<tr>
<td valign="top">Password</td>
<td>****<br />Change Password</td>
</tr>
<tr>
<td>First Name</td>
<td><form:input path="firstName" /></td>
</tr>
<tr>
<td>Last Name</td>
<td><form:input path="lastName" /></td>
</tr>
<tr>
<td>Gender: </td>
<td>
<form:select path="gender">
<form:option value="Male" label="Male" />
<form:option value="Female" label="Female" />
</form:select>
</td>
</tr>
<tr>
<td>Birthday: </td>
<td><form:input path="birthday" id="datepickerpast" readonly="true" /></td>
</tr>
<tr>
<td>Email</td>
<td><form:input path="email" /></td>
</tr>
<tr>
<td> </td>
<td><input type="submit" value="Update" /> <input type="reset"></td>
</tr>
</table>
</form:form>
Controller
#RequestMapping(value = "admin/update-user", method = RequestMethod.POST)
public String processUpdateUser(ModelMap model, #ModelAttribute("user") User user, BindingResult result) throws SQLException {
if (result.hasErrors()) {
model.addAttribute("user", user);
model.addAttribute("pagetitle", "Admin - Update User Details");
return "admin/users/update-user";
} else {
userDao.updateUser(user);
return "redirect:/admin/user-management.html";
}
}
Object Properties with appropriate getters/setters
private int userID;
private String firstName;
private String lastName;
private String username;
private String email;
private Date birthday;
private String gender;

Answer 1

Realized my getter was type Integer but my setter and property was type int. Made all of them Integer and it worked. If someone can explain why there was no error on compile or why it didn't work the way it was, that'd be greatly appreciated.
Sigh, there goes 3 hours of my life.

Answer 2

You got a compiler error because of autoboxing, which allows for the automatic conversion of primitives to their wrapper class alternatives. As to why it didn't work when the getter was using Integer, I can't help you there.