why spring boot webflow validation failed?

Question

I'm trying to convert my webflow.xml file into java config file. After conversion all flows are working fine. but form validation is not happening during form submission and blank form submits. Its working fine with xml configuration. what am i doing wrong here?

I am using spring-boot-starter-parent : 2.0.6.RELEASE

WebFlowConfig.java

 @Bean
    public FlowBuilderServices flowBuilderServices() {
        return getFlowBuilderServicesBuilder().setViewFactoryCreator(mvcViewFactoryCreator()).setValidator(validator())
                .setDevelopmentMode(true).build();
    }

    @Bean
    public LocalValidatorFactoryBean validator() {
        return new LocalValidatorFactoryBean();
    }

User.java

import javax.validation.constraints.NotBlank;

    @Entity
    @Table(name = "user_detail")
    public class User implements Serializable{
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id; 
    @NotBlank(message = "Please enter first name!")
    @Column(name = "first_name")
    private String firstName;
    @NotBlank(message = "Please enter last name!")
    @Column(name = "last_name")
    private String lastName;
    @NotBlank(message = "Please enter email address!")  
    private String email;
    @NotBlank(message = "Please enter contact number!")
    @Column(name = "contact_number")
    private String contactNumber;

signup.jsp

<sf:form method="POST" modelAttribute="user" class="form-horizontal"
            id="registerForm">
            <div class="form-group row">
                <label class="col-form-label col-md-4">First Name</label>
                <div class="col-md-8">
                    <sf:input type="text" path="firstName" class="form-control"
                        placeholder="First Name" />
                    <sf:errors path="firstName" cssClass="help-block redError"
                        element="em" />
                </div>
            </div>


        </sf:form>

please tell me whats wrong i'm doing in my code.

Answer 1

if anyone still needs an answer

@Bean
public LocalValidatorFactoryBean validator() {
    LocalValidatorFactoryBean validator = new LocalValidatorFactoryBean();
    validator.afterPropertiesSet();
    return validator;
}

this one worked for me