I'm trying run three filter functions(Recode,Categorize,Interpolate) described at the bottom of this page http://docs.geoserver.org/stable/en/user/filter/function_reference.html
Recode and Interpolate works fine but Categorize throws me the following exception message. 'java.lang.RuntimeException: Unable to find function Categorize'
What could cause this problem ? Am I supposed to install a plugin on geoserver or what?
The official examples are on http://docs.geoserver.org/stable/en/user/styling/sld-tipstricks/transformation-func.html