@Size and @Pattern annotation are not working in Spring MVC

Added the below jar's to my lib folder in WEB-INF:

• classmate-1.0.0


• javax.el-2.2.4


• javax.el-api-2.2.4


• jboss-logging-3.1.3.GA


• validation-api-1.1.0.Final

The pieces of code I added are:

From model object:

public class UserDetails {

    @Pattern(regexp="(^0-9}*") 
    private String userName;   

    @Size(min=2,max=10)
    private String firstName;    
    private String lastName;
    private String emailId;
    private ArrayList<String> accountType;
    private ArrayList<String> gender;

    @Size(min=2,max=10)
    private Long accountNo;

FromController class:

@RequestMapping(value = "/UserAccount.html", method = RequestMethod.POST)
public ModelAndView userAccountForm(
        @Valid @ModelAttribute("user") UserDetails user,
        BindingResult result) {

    if (result.hasErrors()) {
        ModelAndView model1 = new ModelAndView("LoginForm");
        return model1;
    }

    ModelAndView model1 = new ModelAndView("UserAccount");
    return model1;
}

My dispatcher servlet has

<mvc:annotation-driven/>

Kindly let me know If I missed any basic thing.