how do I solve the ConstraintViolationException in Spring Boot

I wrote a custom validation in spring boot. The custom validation is meant to check if two fields match. Everything works fine until i try to submit the form. Boom i experience the error:

javax.validation.ConstraintViolationException: Validation failed for classes [com.joker.SampleAuthenticationWebApp.model.User] during persist time for groups [javax.validation.groups.Default, ]
List of constraint violations:[
	ConstraintViolationImpl{interpolatedMessage='Passwords do not match!', propertyPath=con_password, rootBeanClass=class com.joker.SampleAuthenticationWebApp.model.User, messageTemplate='Passwords do not match!'}
]

This problem has really hindered my learning progress. Your help would be very much appreciated.<br><br>
PS: I've Scraped SO in search of a solution but all was to no avail.<br><br>The Annotation:

package com.joker.SampleAuthenticationWebApp.validator;

import javax.validation.Constraint;
import javax.validation.Payload;
import java.lang.annotation.*;

@Target({ElementType.TYPE, ElementType.ANNOTATION_TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Constraint(validatedBy = FieldsValueMatchValidator.class)
public @interface FieldsValueMatch {
    String message() default "Fields values don't match!";

    Class<?>[] groups() default {};

    Class<? extends Payload>[] payload() default {};

    String field();

    String fieldMatch();

    @Target({ ElementType.TYPE })
    @Retention(RetentionPolicy.RUNTIME)
    @interface List {
        FieldsValueMatch[] value();
    }
}

The Validator:

package com.joker.SampleAuthenticationWebApp.validator;

import com.joker.SampleAuthenticationWebApp.model.User;
import org.springframework.beans.BeanWrapperImpl;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;

public class FieldsValueMatchValidator implements ConstraintValidator<FieldsValueMatch, Object> {
    private String field;
    private String fieldMatch;

    @Override
    public void initialize(FieldsValueMatch constraintAnnotation) {
        this.field = constraintAnnotation.field();
        this.fieldMatch = constraintAnnotation.fieldMatch();
    }

    @Override
    public boolean isValid(Object value, ConstraintValidatorContext context) {
        try {
            final Object fieldValue = new BeanWrapperImpl(value).getPropertyValue(field);
            final Object fieldMatchValue = new BeanWrapperImpl(value).getPropertyValue(fieldMatch);

            boolean isValid = fieldValue == null && fieldMatchValue == null || fieldValue != null && fieldValue.equals(fieldMatchValue);

            if (!isValid) {
                context.disableDefaultConstraintViolation();
                context.buildConstraintViolationWithTemplate(context.getDefaultConstraintMessageTemplate()).addPropertyNode(fieldMatch).addConstraintViolation();
                return false;
            }
            return isValid;
        }
        catch (final Exception ignore) {
            // ignore
        }
        return true;
    }
}

The User Model:

package com.joker.SampleAuthenticationWebApp.model;

import com.joker.SampleAuthenticationWebApp.validator.FieldsValueMatch;
import org.hibernate.validator.constraints.Length;

import javax.persistence.*;
import javax.validation.constraints.Email;
import javax.validation.constraints.NotEmpty;
import javax.validation.constraints.NotNull;
import java.util.Set;

@Entity
@Table(name = "auth_user")
@FieldsValueMatch(field = "password", fieldMatch = "con_password", message = "Passwords do not match!")
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY, generator = "native")
    @Column(name = "auth_user_id", unique = true)
    private int id;

    @NotNull
    @NotEmpty(message = "First name is compulsory")
    @Column(name = "firstname")
    private String firstname;

    @NotNull
    @NotEmpty(message = "Last name is compulsory")
    @Column(name = "lastname")
    private String lastname;

    @NotNull
    @NotEmpty(message = "Email is compulsory")
    @Email
    @Column(name = "email")
    private String email;

    @NotNull
    @Column(name = "phone")
    private String phone;

    @NotNull
    @NotEmpty(message = "Password is compulsory")
    @Length(min = 5, message = "Password length should be at least 5 characters")
    @Column(name = "password")
    private String password;

    @NotEmpty(message = "Confirm Password field is compulsory")
    @Transient
    private String con_password;

    @NotNull
    @Column(name = "enabled")
    private int enabled;

    @ManyToMany(cascade = CascadeType.ALL)
    @JoinTable(name = "auth_user_role", joinColumns = @JoinColumn(name = "auth_user_id"), inverseJoinColumns = @JoinColumn(name = "auth_role_id"))
    private Set<Role> roles;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getFirstname() {
        return firstname;
    }

    public void setFirstname(String firstname) {
        this.firstname = firstname;
    }

    public String getLastname() {
        return lastname;
    }

    public void setLastname(String lastname) {
        this.lastname = lastname;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getCon_password() {
        return con_password;
    }

    public void setCon_password(String con_password) {
        this.con_password = con_password;
    }

    public int getEnabled() {
        return enabled;
    }

    public void setEnabled(int enabled) {
        this.enabled = enabled;
    }

    public Set<Role> getRoles() {
        return roles;
    }

    public void setRoles(Set<Role> roles) {
        this.roles = roles;
    }
}

I experienced this problem too . The only way to solve this is to include the annotations of @ModelAttribute and @Valid on your controller class for the bean you want to check weather the condition of @FieldsValueMatch(field = "password", fieldMatch = "con_password", message = "Passwords do not match!") is true , after that include the BindingResult right after the bean you want to check . Check if BindigResult hasErrors(), and return what is your next step .

EX:

@PostMapping("/signup")
<br>
public String signup(@ModelAttribute(name = "user") @Valid User user,BindingResult result,Model model)
<br>
if (result.hasErrors())
<br>
return "signup_form";
<br>

Hope this is clear .