I don't think you defined your problem well enough to get detailed advice.
Some points are quite unclear:
- What is Esperanto ? (I assume you don't mean the spoken language)
- Did you actually write code that parses Java ? Using a module ? A full parser or some partial regex-hack ?
Anyways, an intermediate representation for Java code, like for any code really, is a syntax tree. For XML, a good internal representation is the one used by Perl's modules - if your XML isn't too sophisticated, the HoAoH(...) approach of XML::Simple may be what you're looking for.