SpringBootUnity is an MIT-licensed, multi-module Spring Boot 4.1.1 project whose 30 modules each pair Spring Boot with a different technology, written for Java developers who need a runnable, isolated reference for one specific stack rather than a finished product.

What it is

SpringBootUnity is built on Spring Boot 4.1.1, targets JDK 21, builds with Maven 3.9+, and is maintained by houko under the MIT licence. It is not a product but a collection of usage examples: because requirements change, each technology combination lives in its own module, and every module can be packaged and started independently without affecting the others. The core module holds shared utilities, base classes, constants, exceptions and filters, is depended on by every other module, and cannot be run on its own. The remaining modules each demonstrate one technology and can be run one at a time to inspect that technology in isolation.

The concrete problem it solves is stack selection and reference. Instead of committing an application to a single persistence layer or HTTP client, the project shows working alternatives side by side. The mybatis module uses MyBatis as the persistence layer in place of JPA, and the httpinterface module uses the @HttpExchange declarative HTTP client instead of OpenFeign. Elsewhere, Spring Data JPA 7.x with Hibernate remains the default, and the cache module demonstrates the Spring Cache abstraction backed by Caffeine rather than a remote cache. The website module, started by XiaomoMain, combines JPA, FreeMarker pages and an OpenAPI interface and is described as the most complete module in the set.

Key capabilities

• Thirty modules, each independently buildable and startable; core is the shared base package and cannot run alone.
• socket module serves a WebSocket online chat on port 8081, while every other module listens on 8080, so only one module runs at a time.
• Scheduling and background work through scheduled (@Scheduled), async (@Async), and aop, which uses a custom @Loggable annotation to record elapsed time and call counts.
• Messaging coverage through rabbitmq (RabbitMQ send and receive) and kafka (KafkaTemplate with @KafkaListener).
• Data layer coverage through mongodb, multipleSource (multi-datasource configuration and switching), flyway (Flyway migrations read back with JdbcTemplate), and elasticsearch (Spring Data Elasticsearch).
• API documentation with springdoc-openapi 3.x exposing OpenAPI 3.1, monitoring with Micrometer and Spring Boot Actuator, and GraphQL through Spring GraphQL with GraphQL Java.
• Request handling utilities including validation (@Valid / @Validated plus @RestControllerAdvice global exception handling), fileupload with path traversal protection, and ratelimit using a HandlerInterceptor and a fixed time window.

Who uses it and how

• Java developers evaluating one technology: pick the single module of interest, start its main class, and study it without interference from the rest.
• Teams that need a working Spring Boot example against MySQL, Redis, MongoDB, RabbitMQ, Kafka, Elasticsearch or an SMTP server, since each module lists the external services it requires.
• Readers who treat tests as executable documentation: fourteen modules (validation, fileupload, restclient, cache, actuator, async, aop, httpinterface, i18n, ratelimit, graphql, kafka, mail, flyway) ship tests that need no external services, using embedded Kafka, GreenMail embedded SMTP and embedded H2 respectively.
• Contributors adding further Spring Boot technology examples by pull request; the repository shows 885 stars, 432 forks and no open issues.

Getting started

Build with Maven 3.9+ on JDK 21+, then start the main class of the module of interest, such as XiaomoMain for website or ChatMain for socket, after supplying whatever external service that module declares. Running mvn test executes the fourteen self-contained test suites.

How it compares

The facts list no paid products that this project replaces, and they name no comparable tools. SpringBootUnity stands alone in this registry.

When to use it — and when not to

A self-hoster must operate external services per module, which means MySQL, Redis, MongoDB, RabbitMQ, Kafka, Elasticsearch or an SMTP server depending on the example being run, and must run only one module at a time because they share port 8080. Anyone wanting a drop-in library, a single deployable artifact, or a Docker image or compose file will not find one here, and the README is written in Chinese. It is best treated as a working reference to read and adapt, not as a foundation to depend on in production.

mvn clean install

java -jar order/target/order-2020.1.jar

mvn spring-boot:run -pl order

mvn test

java -Xms64m -Xmx2048m -jar order-2020.1.jar >> ./order.log 2>&1 &

<packaging>war</packaging>