In small applications it makes sense to combine Java and Flex code under same project. I’m a big fan of maven and one of my favorite maven plugins is embedded jetty container. This plugin runs jetty directly from maven and supports automatic monitoring and redeployment of java classes and resources. I thought it would be nice to run Java+Flex projects in the same way and have updated SWF file instantly available in the browser immediately after Flex Builder compiles it.

You can find step-by-step instructions on such project set up on my wiki: http://wiki.jpragma.com/creating-new-javaflex-project