Web APIs

Inspect the contract and its failure cases.

1. 1Spring MVC request validation: reject invalid commands before mutation
2. 2Spring MVC ProblemDetail: stable errors without leaking internals
3. 3Spring API pagination: bounded requests and immutable snapshots
4. 4Spring MVC CORS: a browser-origin policy is not authentication

Inspect the state boundary and run its checked fixture.

1. 1Spring reactive foundations: request values and cancel a subscription

Follow the input contract, inspect failures and run the checked source.

1. 1Spring WebFlux SSE: emit bounded receipt events and test HTTP encoding
2. 2Spring WebFlux cancellation: observe downstream cleanup without undoing work

Read the contract, run the checked fixture and inspect the rejected path.

1. 1Spring MVC conditional GET: validate the representation tag

Run the checked example, then inspect its rejected path and cost boundary.

1. 1Spring MVC consumes and produces: 415 and 406 are different failures
2. 2Spring MVC nested validation: reject a bad line before the handler

Check the invariant, run the fixture and test a rejected boundary.

1. 1Spring If-Match writes: reject a stale receipt revision

Run the source-kit fixture and inspect its rejected boundary.

1. 1Spring POST idempotency keys: replay the same receipt result
2. 2Spring retry and stale-write checks: choose the right HTTP contract

Run the source-kit test and inspect the rejected case.

1. 1Spring MVC validation paths: object constraints and method parameters
2. 2Spring MVC validation errors: one public ProblemDetail for two failure paths

Trace a tenant-scoped command from token to committed rows.

1. 1Spring POST idempotency keys: bind replay to tenant and command

Check byte, storage and operational health boundaries.

1. 1Spring MVC multipart receipt import: validate before storing
2. 2Spring multipart size limits: enforce parser and application budgets
3. 3Spring CSV uploads: reject malformed UTF-8 and an unknown header

Follow the boundary from local fixtures to a release test.

1. 1Spring RestClient request factories: pin the transport you test
2. 2Spring HTTP client timeouts: bound the call inside the request deadline
3. 3Spring HTTP retries: only replay a command with a defined identity

Read the checked transport, timeout and replay contracts.

1. 1Spring RestClient transport: run the factory you configured
2. 2Spring RestClient 503 response: count attempts before adding a retry
3. 3Spring RestClient read timeout: reject a server that accepts but stalls
4. 4Spring HTTP timeout after POST: the write may already exist
5. 5Spring HTTP replay key: two requests, one modeled reservation

Follow the request or object-graph boundary through its failure cases.

1. 1Spring MVC request lifecycle: from servlet filter to response body
2. 2Spring Filter versus HandlerInterceptor: choose the right request boundary

Read the operation contract, then test its failure and capacity boundaries.

1. 1Spring WebSocket and STOMP: authenticate the handshake, authorize messages

Run the source-kit test, then inspect the failure and ownership rule.

1. 1Spring MVC @ModelAttribute: allowlist fields before binding a form

Check creation, routing and failure at the exact framework boundary.

1. 1Spring MVC mapping params: route a format choice before the handler runs
2. 2Spring MVC exception handlers: a controller-local handler wins before global advice
3. 3Spring @RestControllerAdvice selector: apply an error policy to one controller family

Check schema execution, authorization, costs and verification scope.

1. 1Spring GraphQL schema nullability: trace one field failure through the response
2. 2Spring GraphQL errors: distinguish validation, resolver failure and nullable data

Read the application contract and its unverified integration boundary.

1. 1Spring AI structured output: validate the parsed object before any write

Trace the failure path, test the rejected case and follow the connected lesson.

1. 1Spring behind a proxy: trust forwarded headers only after the edge strips them

Follow state and ownership across process boundaries.

1. 1Spring GraphQL @BatchMapping: collapse N+1 lookups without changing field behavior

Follow one operation through its failure path and linked application boundary.

1. 1Spring Cloud Gateway filter order: pre and post phases reverse
2. 2Spring Cloud Gateway retry: idempotency, buffered bodies and the byte budget
3. 3Spring STOMP slow clients: send buffer and message-size limits
4. 4Spring STOMP simple broker versus relay: the multi-instance boundary
5. 5Spring HTTP service client: the interface is a contract, not a transport policy
6. 6Spring HTTP service client retries: an interface cannot prove the server did not commit

Follow the operation through failure, recovery and linked tests.

1. 1Spring Cloud Gateway circuit breaker: a fallback is an API response contract
2. 2Spring STOMP broker relay: credentials and broker availability are separate from user identity
3. 3Spring WebSocket reconnect: recover state after an unobserved gap
4. 4Spring HTTP service groups: configure one host policy for several interfaces
5. 5Spring WebClient exchangeToMono: decode the response inside its callback
6. 6Reactive HTTP service client: the proxy returns a publisher, not a completed call

MVC async capacity, streaming disconnects and WebClient decoding limits.

1. 1Spring MVC async executor: bound Callable work before requests pile up
2. 2Spring MVC streaming response: stop work when the client disconnects
3. 3Spring WebFlux codec memory budget: distinguish aggregation from streaming
4. 4Spring WebClient status-specific decoding: consume one branch and close the rest

Private response caches, range downloads, attachment names, static asset versions, client context and STOMP permissions.

1. 1Spring MVC private Cache-Control: decide who may retain a receipt
2. 2Spring MVC byte ranges: resume an authorized receipt download
3. 3Spring MVC Content-Disposition: produce a safe attachment filename
4. 4Spring MVC versioned static assets: cache immutable bytes by content
5. 5Spring WebClient attributes versus Reactor Context: choose the right request scope
6. 6Spring WebClient request audit: log route identity without payload leakage
7. 7Spring STOMP authorization: separate SEND from SUBSCRIBE permissions