As of SPR-8093, jmxremote_optional.jar is present on the build
server in jre/lib/ext, but it is not by default present on local
developer / user machines, meaning that the build ends up broken
by default.
Issue: SPR-8089, SPR-8093, SPR-8458
git-svn-id: https://src.springframework.org/svn/spring-framework/trunk@4560 50f2f4bb-b051-0410-bef5-90022cba6387