Each programming language has its own mindset so analogies or comparisons with other programming languages provide little help or value if we want to use it well.
It is all about developing the mindset, and of course we don’t need to wait until Java will run into Flash Player 
It’s interesting to read the issues (from Java developer point of view), read more
http://bozhobg.wordpress.com/2008/11/27/why-i-might-not-want-to-use-flex/
http://joshuajava.wordpress.com/2008/11/23/why-you-might-not-want-to-use-flex/