Pure Functional Java Builder

Builder.java

import static java.util.Objects.requireNonNull;

public class Builder {

  public static void main(String[] args) {
    User user = User.builder().id(1).name("toni").email("toni@home").build();

    System.out.println(user);
  }
}

record User(
  Integer id,
  String name,
  String email) {

  public User {
    requireNonNull(id, "id cannot be null");
    requireNonNull(name, "name cannot be null");
    requireNonNull(email, "email cannot be null");
  }

  public static IdStep builder() {
    return id -> name -> email -> () -> new User(id, name, email);
  }
}

interface IdStep {
  NameStep id(int id);
}

interface NameStep {
  EmailStep name(String name);
}

interface EmailStep {
  UserBuilder email(String email);
}

interface UserBuilder {
  User build();
}