The tutorial http://sinnerinc22.blogspot.de/2010/07/adding-syntax-highlighter-to-jamwiki.html describes how to enable syntax highlighting in JAMWiki.
My problem is that in the recent version of JAMWiki v1.2 the two files to be modified WEB-INF/jsp/top.jsp and WEB-INF/jsp/close-document.jsp do not exist any longer…
There is a third-party syntax highlighting tag extension available with JAMWiki 1.2 link that may work for you