Some simple code I can look at?

I've been attempting to learn Java and Bukkit for a while, but my biggest problem is fitting code together properly. I feel I could better myself by looking at predetermined source code for a plugin that gives basic examples. (No a Hello World script will not do. I need more important stuff like saving and reading from text files, just to pick a few)
I don't need to see everything, but it would be nice to see each basic code put into action, or even better, detail.