@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy = {EmailValidation.EmailValidator.class})
public @interface EmailValidation {

String regularExpression() default "^[_A-Za-z0-9-\\+]+(\\.[_A-Za-z0-9-]+)*@"n" +
        "tt+ "[A-Za-z0-9-]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$";
String message() default "Wrong input";


 class EmailValidator implements ConstraintValidator<EmailValidation,User>{

 private static String regEX;
 private static String message;
 private static String emailField;

 public void initialize(EmailValidation email) {

     regEX = email.regularExpression();
     message = email.message();
     emailField = User.getEmail();
 }

 public boolean isValid(User user, ConstraintValidatorContext constraintValidatorContext) {
     return emailValidation(user);
 }

 private boolean emailValidation(User user){

        if(!(emailField.matches(regEX))){

            System.out.print("Checking");

            System.out.print(message);
            return false;

        }


     System.out.print("AllMatches");

     return true;
 }
}

public class ApplTest {

public static void main(String [] string){

    User user = new User("Aleksey","13224","Aleksey.Alekseev88@gmail.com");

  }
}

public class User {

public static String getUserName() {
    return userName;
}

public static String getPassword() {
    return password;
}

public static String getEmail() {
    return email;
}

public User(String userName, String password, String email) {

    setUserName(userName);
    setEmail(email);
    setPassword(password);
}

private static void setUserName(String userName) {
    User.userName = userName;
}

private static void setPassword(String password) {
    User.password = password;
}

private static void setEmail(String email) {
    User.email = email;
}

private static String userName;
private static String password;

@EmailValidation // Не работает!
private static String email;