If you're using Flex to complement your Java developments, there appears to be strong evidence your existing Java framework skills will come in handy. As this post by Simeon Bateman points out, frameworks like Swiz, Spring ActionScript and Mate -- all targeting ActionScript, Flex's/Flash's scripting language -- have a strong influence from similar frameworks you've probably worked with in Java. Read Simeon Bateman's post 'Actionscript 3 just keeps getting a little more Java': http://blog.simb.net/2009/01/09/actionscript-3-just-keeps-getting-a-little-more-java/