Grokking Spring Boot

It is a written course that teaches Java developers to build a backend service with Spring Boot and to explain how each part of Spring makes that service work. One booking service for an event ticketing app grows from a single endpoint to a secured, tested service ready for production.

It is for Java developers who are starting with Spring Boot, and for developers who already use it but want to understand what it does for them. It suits a backend engineer joining a Spring team and a developer moving from another framework.

You need basic Java: classes, interfaces, collections, and exceptions. No earlier Spring experience is needed. The course reviews the modern Java features that Spring code relies on, such as lambdas, streams, Optional, records, and annotations, before it uses them.

It uses Spring Boot 4 on Spring Framework 7, with Java 21 for the Spring code. Every Spring listing, setting, log line, and error message in the lessons comes from a real run of that version, not from memory or an older guide.

Most courses teach which annotation to add. This course also explains the mechanism behind it, and several lessons build a small version of a mechanism in plain Java first: a container that reads constructors, a proxy that wraps a method in a transaction, and a condition evaluator like the one auto-configuration uses.

Yes, for the plain Java programs. They use only the Java standard library and run in the course player with the Run button. Spring code needs a build tool and a running server, so it is shown read-only together with the real output it produced.

Yes. It covers connection pools, plain SQL with JdbcClient, JPA entities and Spring Data repositories, lazy and eager loading, the N+1 query problem, projections, and Flyway migrations, then transactions in depth: propagation, isolation levels, rollback rules, the self-invocation trap, and optimistic and pessimistic locking.

Yes. It explains the security filter chain, authentication and authorization, password hashing, stateless APIs with JWT tokens, sign-in with OAuth2, method security with @PreAuthorize, and CORS and CSRF, and then secures the booking API for customers and venue staff.

It shows when to use plain unit tests without Spring, slice tests such as @WebMvcTest and @DataJpaTest, full application tests with @SpringBootTest, tests against a real database with Testcontainers, tests of security rules, and tests of the HTTP layer.

Yes. It covers caching, asynchronous methods, virtual threads, connection pool sizing, calls to other services, retries, and timeouts, then application events, Kafka, the transactional outbox, Actuator, health probes, metrics and tracing, container images, graceful shutdown, and a production checklist.

Every lesson ends with practice questions and folded answers, and many lessons include Java programs you can run and change. Each chapter ends with an adaptive assessment that draws a fresh set of questions on every attempt, and the course closes with an adaptive final exam across all chapters.