Weak-area drill · from your mock

Spring Core Internals

You passed the mock at 90% — the only soft spot was Core (71%). This drills the exact five confusions that cost you, plus the one Boot miss, from fresh angles.

The six you missed — and the fix ApplicationContext vs BeanFactory (eager/lazy); where proxies are created; the exact stereotype set; disambiguation (@Order is a decoy); @Repository's special power; and CommandLineRunner. Master these and Core becomes your best section.

60-second refreshers

Confusion	The nail-it fact
`ApplicationContext` vs `BeanFactory`	ApplicationContext extends BeanFactory and pre-instantiates singletons eagerly. A plain BeanFactory is lazy. AppContext also adds events, i18n, resource loading, and auto-registers post-processors.
Where proxies are created	A BeanPostProcessor creates the proxy in `postProcessAfterInitialization` — the last creation step. BFPP works on definitions; BPP works on instances.
Stereotypes	`@Component`, `@Service`, `@Repository`, `@Controller`, `@RestController`. `@Bean` is NOT one — it's a method-level annotation, not a scanned class.
Disambiguation	`@Qualifier`, `@Primary`, and matching the bean name pick which bean to inject. `@Order` does NOT — it only orders items in a collection/advisor chain.
`@Repository`'s power	The only stereotype that adds real behaviour: persistence exception translation (SQLException → DataAccessException).
`CommandLineRunner`	Runs code once, after the whole app context is ready (with access to args). Different from `@PostConstruct`, which runs per-bean right after that bean's DI.

Exam strategy: slow down on "select all" Two of your six misses were select-all questions — they give no partial credit, so one wrong tick loses the whole mark. On those, verify every option individually, including the tempting decoy.

Drill — 14 questions, fresh angles

Same concepts, re-attacked so you're recognising the idea, not a memorised sentence. Options shuffle on every load.

Then re-take the mock Reload the Full Mock Exam for a fresh random 60. With these six locked in, aim to push Core to 90%+ and your overall into the mid-90s. You're already comfortably passing — this is polish.

I'm your teacher — ask me anything. Want me to trace why the proxy is created in postProcessAfterInitialization (not earlier), or any other of these in depth? Ask.

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