If you want to transform fixed length files (batch, or mainframe files) to XML (and so forth) you have to use XSLT2. Altova Map Force does not support outputting XSLT2 stylesheets in the fixed length format, so you are on your own.

For Java, you can use the open source Saxon parser:

http://www.saxonica.com

Here are some examples of XSLT2 style sheets transforming to fixed length:

http://www.topxml.com/xsltStylesheets/xslt_non_XML.asp