Claude
e4b5636f7c
Three companion modules verifying and rewriting the Boot 4.1.1 / Framework 7.0.9 story for three older articles: the javax->jakarta.validation namespace fix plus Jakarta Validation 3.1 record-validation clarification, ETag/ conditional-request APIs re-verified unchanged plus the starter rename, and RestTemplate Basic Auth rebuilt on RestClient with the exchange() trap called out. 19 real passing tests generate every transcript quoted from the three companion articles. Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01EQNA6DJ9VgCtW6zhCE8Xud
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3. The Boot 4 starter split, and the exchange() trap
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Source: pom.xml.
spring-boot-starter-restclient is not optional in Boot 4
The original article's spring-boot-starter-web dependency was, on Boot 3, sufficient to get an
auto-configured RestTemplateBuilder bean for free. On Boot 4.1, HTTP client support moved into
its own starter, confirmed the same way every version fact in this repository is confirmed --
build a throwaway project and read the real dependency tree:
$ mvn dependency:tree # against spring-boot-starter-parent:4.1.1 + spring-boot-starter-webmvc only
spring-boot-starter-webmvc alone does not pull in spring-boot-restclient. Leave
spring-boot-starter-restclient off this module's pom.xml and the auto-configured
RestClient.Builder this chapter's code depends on is simply not there -- a NoSuchBeanDefinitionException
at startup, not a subtle behavioural difference. This module declares it explicitly.
The trap this module deliberately avoids
RestClient has its own exchange() method, and it means something different from
RestTemplate.exchange(): RestClient's exchange() disables the default status handlers, so a
4xx or 5xx response is silently returned to you instead of thrown. Every example in this module
uses retrieve() for exactly that reason -- retrieve() keeps the throw-on-4xx/5xx behaviour this
Basic Auth demo relies on (see docs/output/03-restclient-no-credentials-401.txt).
A team that mechanically renames restTemplate.exchange(...) call sites to
restClient.exchange(...) during a migration ships code that stops noticing failed requests. The
RestTemplate to RestClient migration guide
covers this trap, the full method-mapping table, and the three behavioural differences that matter
in more depth than a Basic Auth-focused rewrite has room for.
Going deeper
- RestTemplate to RestClient Migration Guide -- the exchange() trap, timeouts, and the full mapping table
- Spring Boot 4 HTTP Service Clients (@HttpExchange) -- the declarative layer built on top of RestClient
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