In order to compile from the source files or execute the SOAP-over-P2P.jar, you should have the following jars in your classpath:
beepcore.jar, cmsshell.jar, cryptix32.jar, cryptix-asn1.jar, instantp2p.jar, jxta.jar, jxtacms.jar, jxtaptls.jar, jxtasecurity.jar, jxtashell.jar, log4j.jar, minimalBC.jar, org.mortbay.jetty.jar, servlet.jar
All these jar files get are part of the JXTA shell installation.

JxtaGui class is the point to start (it is included in SOAP-over-P2P.jar). A sample batch file to exec SOAP-over-P2P is as follows:

java -classpath SOAP-over-P2P.jar;./;./lib/jxta.jar;./lib/log4j.jar;./lib/beepcore.jar;./lib/jxtasecurity.jar;./lib/org.mortbay.jetty.jar;./lib/servlet.jar;./lib/cryptix-asn1.jar;./lib/cryptix32.jar;./lib/jxtaptls.jar;./lib/minimalBC.jar JxtaGui