rstoyanchev/spring-framework — pull request #11 by wilkinsona (2013-07-01 12:00:52+00:00)
Title: Verify types when setting header

When a header is being set, verify that the type that's provided is
legal for the header that's been set. For example, the error channel's
type must be a MessageChannel or a String.

The method that performs type verification is protected so that it
can be overriden by sub-classes. It is expected that an overriding
method will call the super method.