final CodecRegistry pojoCodecRegistry = fromRegistries(getDefaultCodecRegistry(), fromProviders(PojoCodecProvider.builder().conventions(asList(
  Conventions.ANNOTATION_CONVENTION, Conventions.SET_PRIVATE_FIELDS_CONVENTION, Conventions.OBJECT_ID_GENERATORS)).automatic(true).build()));

// Create settings
final MongoClientSettings.Builder settings = MongoClientSettings.builder()
        .applyToClusterSettings(builder -> builder.hosts(singletonList(serverAddress)))
        .uuidRepresentation(UuidRepresentation.STANDARD)
        .codecRegistry(pojoCodecRegistry)
        .credential(MongoCredential.createCredential(username, database, password.toCharArray()));

this.mongoClient = MongoClients.create(settings.build());

public class Account {
    private final UUID id;
    private String username;
    private Date createdAt;

    public Account(@Nonnull UUID id, @Nonnull String username, @Nonnull Date createdAt) {
        this.id = id;
        this.username = username;
        this.createdAt = createdAt;
    }

    @BsonCreator
    public Account(@BsonProperty(value = "_id") UUID id) {
        this.id = id;
    }

    /**
     * This is unique id of the player (Mojang UUID)
     *
     * @return The player unique id
     */
    public UUID getId() {
        return id;
    }

    /**
     * This is a name of the player (Minecraft account name)
     *
     * @return The player name
     */
    public String getName() {
        return username;
    }

    /**
     * This is a created date
     *
     * @return The created date
     */
    public Date getCreatedAt() {
        return createdAt;
    }

    @Override
    public boolean equals(Object obj) {
        if (obj instanceof Account) {
            return ((Account) obj).getId().equals(id);
        }

        return false;
    }

    @Override
    public String toString() {
        return "Account{"
                + "id='" + id + "'"
                + ",username='" + username + "'"
                + ",createdAt=" + createdAt
                + "}";
    }
}

Actual : Account{id='2df03368-a4c6-4b05-8807-fca12ab50134',username='null',createdAt=null}
Excepted : Account{id='2df03368-a4c6-4b05-8807-fca12ab50134',username='orblazer',createdAt=null}