spring-projects/spring-integration — pull request #1302 by artembilan (2014-10-22 11:15:07+00:00)
Title: INT-3535: Fix `JmsHM` to not override properties

JIRA: https://jira.spring.io/browse/INT-3535

Previously when `DefaultJmsHeaderMapper` overrided values, which had been able to be populated by the `MessageConverter`.

Since `MessageConverter` result has a precedence which is closer to JMS, skip those custom `MessageHeaders` which already has been populated by `MessageConverter`