The "apply" XSL tag raises an exception when the specified XSLT calls a function in an extension class: java.lang.IllegalAccessError: try to access field org.apache.xalan.xpath.Extensi onFunctionHandler.class$com$ibm$bsf$BSFManager from class org.apache.xalan.xslt. ExtensionNSHandler Xalan will successfully process the same XML/XSLT when run from a command-line utility.
Cahanged product to taglibs
The XSL taglib is based on Xalan1 and is not compatible with Xalan 2. There are two alternatives for XSL which have more features, XTAGS and Standard taglibs.