As of now, you can use any combination of metadata. Metadata combinations which are not pre-defined will be compiled at runtime (wherefore the translation of a query can take a few seconds longer). If you want to use this feature you have to use JDK (and not JRE) to run Odysseus. The source code of the generated classes are stored in the Odysseus home directory under ~/odysseus/CodeGen. For further information see Meta data.