spring-projects/spring-integration — pull request #1276 by artembilan (2014-09-12 12:20:04+00:00)
Title: INT-3516: Allow `Optional<>` in POJO method args

JIRA: https://jira.spring.io/browse/INT-3516

* Add `Optional<>` support for `@Header` in the `MessagingMethodInvokerHelper`
* Add `Optional<>` test-case
* Change `sourceCompatibility` for test to the Java 8