What standard of WfMC? - XPDL - Conformance - BPAF - Wf-XML
Last 2 no (does anyone? or even want to?), The first not in jBPM itself, but the Process Virtual Machine used in jBPM 4 is used by Bonita from ObjectWeb. The conformance is debatable, Regarding the interfaces, (http://www.wfmc.org/reference-model.html) partly yes, partly no.