Prior to this commit, HTTP client builders auto-configured by Spring
Boot would be eagerly instantiating resources, even if those were not
used by the application.
This commit makes the `RestTemplateBuilder` bean as Lazy.
`WebClient.Builder` was already a prototype bean, but some of its
dependencies could consume resources, like the `HttpClientConnector` and
the related infrastructure. This commit makes those pieces lazy.
Note that since those components are meant to help instantiate actual
HTTP clients for application components, making them lazy won't make any
difference at runtime since they'll be used during context refresh, or
they won't be used at all.
Closes gh-19549
Prior to this commit, active profiles were being added to the Spring Boot
application environment by setting the `spring.profiles.active` property.
This could result in profiles getting parsed differently than other uses of `@ActiveProfiles`.
Setting the profiles directly in the `Environment` prevents this parsing.
See gh-19556
Prior to this commit, the `ErrorController` would override the original
error response status if the error map cannot be written due to content
negotiation with the HTTP client. In that case, the error handling
infrastructure returns a `406 Not Acceptable` response.
This commit improves the `ErrorController` so that
`HttpMediaTypeNotAcceptableException` instances thrown by that
controller are not returned as is but instead we write the error
response with an empty body and the original HTTP error status.
Fixes gh-19545
See gh-19522
Stephane Nicoll
dreis2211
Brian Clozel
Madhura Bhave
Andy Wilkinson
Matthias Stock
Johannes Graf
Scott Frederick