Hi Madhumita.
Thank for ypur answer
I tried to put the jars in /opt/gluu/jetty/oxauth/lib/ext and also in /opt/gluu/jetty/oxauth/custom/libs, and /opt/gluu/jetty/oxauth/custom/libs/ext but I guess some steps are missing to make it work because I always have the same error.
(I also set the read and execution right to this folders and jar files)