Configure MongoDB in Spring Data

build.gradle

compile("org.springframework.boot:spring-boot-starter-data-mongodb")
compile group: 'org.mongodb', name: 'mongo-java-driver', version: '3.4.2'

application.properties

spring.data.mongodb.uri=mongodb://localhost/pupli

User

import org.springframework.data.annotation.Id
import org.springframework.data.mongodb.core.mapping.Document

@Document(collection = "users")
public class User implements Serializable {

    @Id
    public String id;

    public String userName;

    public String password;

    public String firstName;

    public String lastName;

    public static String COL1_id(){
      return "id"
    }

    public static String COL2_userName()
    {
        return "userName"
    }

    public static String COL3_password()
    {
        return "password"
    }

    public static String COL4_firstName()
    {
        return "firstName"
    }

    public static String COL5_lastName()
    {
        return "lastName"
    }
}

References
https://spring.io/guides/gs/accessing-data-mongodb/
http://www.baeldung.com/spring-data-mongodb-tutorial
https://www.mkyong.com/mongodb/spring-data-mongodb-hello-world-example/
https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-nosql.html