Spring MVC with hibernate validation doesn’t work

I have some problems with hibernate validations with Spring. I did everything as explained in an online tutorial, but it’s not working and I just go to the next page without validation error.

import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;

public class Customer {

private String firstName;

@NotNull()
@Size(min=1, message = "this field must not to be empty")
private String lastName;

Controller:

@RequestMapping("/processForm")
public String processForm(@ModelAttribute("customer") @Valid Customer 
                          customer, BindingResult bindingResult) {
    if(bindingResult.hasErrors()) {
        return "customer-form";
    }
    return "customer-confirmation";
}

customer-form.jsp

<form:form action="processForm.form" modelAttribute="customer">
    First name: <form:input path="firstName"/>
    <br>
    Last name (*): <form:input path="lastName"/>
    <form:errors path="lastName" cssClass="error"/>
    <input type="submit" value="Submit"/>
</form:form>

So, there are no errors in BindingResult when I have an empty field for lastName. What am i doing wrong?

Answer

Add hibernate-validator in your classpath if it does not exist already. If you are using any build tool like gradle or maven just add hibernate-validator to dependencies.

For example:

Gradle:

compile group: 'org.hibernate.validator', name: 'hibernate-validator', version: '6.0.13.Final'

Maven:

<dependency>
    <groupId>org.hibernate.validator</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>6.0.13.Final</version>
</dependency>