jbpm is fairly logical. If you look at a processdefinition, you'll see task-nodes and... surprisingly there is a tasknode class. This in the javadoc you'll see that there is a nice method for what you want...
So the deeper meaning of this story is to think logically and look a little further.
otoh, this is a little to low-level... managing tasks from the developer point of view should be done via taskinstance objects... and surprisingly... there is a nice method to
Don't you be mean to me ! :)
( public java.util.List getAvailableTransitions() , you were right it was really kind of hard to find :) )
mean is my middle name :-P