Java Classes -> JSON Schema

Would it be possible to take my own Java classes produced from jsonschema2pojo and produce JSON Schema from Jsonix schema compiler? My JSON doesn't correspond to an XSD, we convert the XML to JSON with a style sheet and add prefixes to attributes, comments and arrays: @, # and -. Is there another tool which might work? Jackson? From what I've seen, it takes a single class, but there's potential for several classes. I realize I can modify the JSON schema generated from Jsonix, but I'm looking for a slightly easier way. Thanks for any pointers you can give.