Spring Boot

Bean scopes and lifecycle callbacks: how many instances of a bean exist, how long each lives, and who cleans it up.

Intermediate to Advanced7 cards · 4 qnot started

Handling errors consistently in a REST API: custom exceptions, @ExceptionHandler, @RestControllerAdvice, status codes and one error body.

Intermediate to Advanced7 cards · 5 qnot started

Spring Data JDBC vs Spring Data JPA: persistence context, dirty checking, lazy loading, aggregates, and when to choose each.

Intermediate to Advanced7 cards · 4 qnot started

The JPA entity lifecycle: the four states an entity can be in, the operations that move it, and when its SQL runs.

Advanced7 cards · 5 qnot started

Transactions with @Transactional: what it wraps, when it rolls back, why self-calls skip it, and REQUIRES_NEW.

Intermediate to Advanced7 cards · 4 qnot started

Caching in Spring Boot: @Cacheable, @CachePut and @CacheEvict, cache keys, caching strategies, and the default provider's limit.

Intermediate to Advanced7 cards · 5 qnot started

What a Spring bean is, the two interfaces behind the container, and the fixed lifecycle every bean follows.

Beginner to Intermediate6 cards · 4 qnot started

What Spring Boot adds to Spring: @SpringBootApplication, auto-configuration, and the conditions that decide which beans it creates.

Intermediate to Advanced6 cards · 4 qnot started

Spring Boot starters and the embedded server: one dependency instead of a dozen, and a web server inside your own jar.

Intermediate to Advanced6 cards · 4 qnot started

Configuring a Boot application: where a property can come from, which source wins, profiles, and binding properties into code.

Intermediate to Advanced6 cards · 4 qnot started

Mapping HTTP requests to controller methods: verbs and paths, reading request data, and choosing the response.

Intermediate to Advanced6 cards · 4 qnot started

Validating request input with Bean Validation: constraint annotations, @Valid, and field-by-field error responses.

Intermediate to Advanced6 cards · 4 qnot started

Spring Data repositories: CRUD without SQL, queries derived from method names, @Query, and what save() really does.

Intermediate to Advanced6 cards · 4 qnot started

Finding why a Spring Boot API is slow: the N+1 query problem, slow remote calls, and measuring before optimising.

Intermediate to Advanced6 cards · 4 qnot started

Wiring beans together: constructor injection, stereotype annotations, choosing between two candidates, and @Bean methods.

Intermediate to Advanced7 cards · 5 qnot started

Dependency injection: why a class should be handed its dependencies instead of creating them, shown without Spring first.

Beginner5 cards · 4 qnot started