One more thought. Try both of these:
1) Create a new workspace and move your project to it. Eclipse keeps a lot of crud in the workspace/.metadata directory, perhaps that is where the old class with that method is hiding.
2) If that doesn't fix the issue, reinstall Eclipse. Taht's as simple as unzippin it into a different location (you don't evene have to remove the old one). Then run it. Perhaps there is a plugin that is mistakenly caching things in the eclipse/plugins directory (I've ran across a few plugins that do this).