JavaFlow doesn't work in trunk at all, because the class AbstractContinuation doesn't exist either in cocoon-javaflow.block.jar nor in src. There are just these few classes in org\apache\cocoon\components\flow\java:
CocoonContinuationContext.class
JavaInterpreter.class
VarMap.class
VarMapHandler.class
Things are pretty different ...but I am pretty sure it's working ;-)
What problems do you have?
cheers -- Torsten