Custom Marshallers

Lists / Collections of X

http://stackoverflow.com/questions/21592731/grails-xml-marshalling-change-default-list-root-element-name

http://mrhaki.blogspot.com.uy/2014/02/grails-goodness-customize-root-element.html

http://pastebin.com/uddpegzG

Marshalling and nulls

http://stackoverflow.com/questions/21788719/how-to-exclude-null-properties-from-marshalling-with-grails-xml-marshaller

JSON and XML

https://jwicz.wordpress.com/2011/07/11/grails-custom-xml-marshaller/

Where to put custom marshallers

https://gist.github.com/ktuukkan/8753246

Converters source code

http://grepcode.com/file/repo1.maven.org/maven2/org.grails/grails-plugin-converters/2.5.1/grails/converters/XML.java#XML

http://grepcode.com/file/repo1.maven.org/maven2/org.grails/grails-plugin-converters/3.0.4/org/grails/web/converters/marshaller/xml/DomainClassMarshaller.java?av=f