When I say "metadata" it's important to distinguish between the actual associations between classes/methods/fields and these attributes and how these associations are done. Using tags in source code is *one* way to do this, but certainly not the only one. As but one example, in our own AOP/metadata framework we allow attributes to be defined in XML-files which are read at startup and added to the set of runtime attributes gathered through source code doclet tags. This way we can have one set of attributes which are always the same (=defined in code) and some of which are more deployment oriented (=defined in XML). It seems like most people think "doclet tags" when you talk about metadata, but that's (to me) just one input method among others.