Actually in Eclipse Indigo thru Oxygen, you have to go to the Types template Window -> Preferences -> Java -> Code Style -> Code templates -> (in right-hand pane) Comments -> double-click Types and make sure it has the following, which it should have by default:
/**
* @author ${user}
*
* ${tags}
*/
and as far as I can tell, there is nothing in Eclipse to add the javadoc automatically to existing files in one batch. You could easily do it from the command line with sed & awk but that's another question.
If you are prepared to open each file individually, then selected the class / interface declaration line, e.g. public class AdamsClass { and then hit the key combo Shift + Alt + J and that will insert a new javadoc comment above, along with the author tag for your user. To experiment with other settings, go to Windows->Preferences->Java->Editor->Templates.
