You may not have noticed, (what, you aren't subscribed to the BlazeDS commits forum?) but a few weeks ago Mete committed an enhancement that adds a Java AMF client API to the flex-messaging-core.jar file in BlazeDS.
You can find a specification posted here and its linked from the Developer Documentation page.
What does this do? Well, you can use this API to call (from Java) Flash Remoting end points in BlazeDS, LiveCycle Data Services, ColdFusion, PHP or whatever you have that supports AMF. Which of course is a published specification.
This feature is available in any nightly build after 184.108.40.20602 or in the trunk nightly build. Find those builds on the BlazeDS build download page.