HI.

I've been playing with jmapper (I love it!). However I've hit an issue I think is probably easy to solve.

I have an XML conversion configured to help out when converting between two JAXB2 generated classes. My conversion looks a little like this (package name redacted):

<class name=".....FlightLeg">
    <global></global>
    <conversion name="durationConversion" from="legDuration" to="legDuration" type="STATIC">
        ${destination.type} result = new ${destination.type}();
        result.setMeasure(${source}.getMeasure());
        return result;
    </conversion>
</class>

When the jmapping config gets written by jmapper (version 1.3.3.1) I get:
ERROR com.googlecode.jmapper.JMapper - IllegalArgumentException: Illegal group reference

I've traced the issue to com.googlecode.jmapper.util.GeneralUtility line 389, specifically the replaceAll operation. It looks like the var.getValue() (in my case replacing the mapping placeholder) string contains a $. As the second argument for the replaceAll function is also a REGEX (see https://stackoverflow.com/questions/11913709/why-does-replaceall-fail-with-illegal-group-reference) this causes the exception. The dollar needs to be escaped, or alternatively (from the String#replaceAll javadoc):

"Note that backslashes () and dollar signs ($) in the replacement string may cause the results to be different than if it were being treated as a literal replacement string; see Matcher.replaceAll. Use Matcher.quoteReplacement(java.lang.String) to suppress the special meaning of these characters, if desired."

I hope that helps you track the error. I'd love to recommend jmapper use in my project, it's a great innovation. If you need any more data please get in touch.