E.g. at HP Labs, for Lab 2E, instead of the usual command:
xslp catalog2e.xml
C:\training\xml\2> java -Dhttp.proxyHost=proxy.hpl.hp.com -Dhttp.proxyPort=8088 com.kav.xsl.XSLProcessor -i catalog2e.xml -s lab2.xsl -o render.htm