* Introduce `MapBuilder` and its custom inheritor - `MailHeadersBuilder` * Add `HeaderEnricherSpec.headers(MapBuilder)` and `.headers(Map)` * Change `MailTests` to use new `Mail.headers()` and new `IntegrationFlowDefinition.enrichHeaders(MapBuilder)` * Change `mailapi` dependency to the IO's `javax.mail` Polishing - Add headerExpressions() More Polishing - Add Configurer Polishing - PR Comments - Move MapBuilderConfigurer to superclass. - Move PropertiesBuilderConfigurer into PropertiesBuilder.
Spring Integration Java DSL
See the Spring Integration Java DSL Reference for more info.