Thanks for the discussion. I think for things like map data or mission editor data I will use something like either JSON or XML (probably JSON). This is slightly different in that the intent is to allow the programmer to define the Components themselves outside of code. So it isn't about loading data into existing objects so much as defining the objects themselves.
One thing I (stupidly) forgot was that the code wouldn't even compile if it used objects that did not exist until run time. Another option would be to have the program read the text file, generate Java code, and compile it to a jar file that is then imported into the game. The question is, is it worth it?
On the plus side, rather than writing n class files, one for each component, I would only have a single file to deal with. And I could automate the jar generation to make it easy to incorporate when I've made changes I want pushed to the game.
On the down side, it is seems like I may be getting snared in a weaker version of the game engine trap.