NoClassDefFoundError java.lang.System

In the QA Lab we come across an issue when trying to run the JBoss AS test suite on VMs (see trace level log bolow). Consequences are that minimal server doesn't shutdown and test suite fails on starting the all configuration.

To reproduce:
Can be reproduced on a VM with sun jdk15 versions including 1.5.0_12.
Try ssh to qa01.qa.atl.jboss.com. On any issue ask in jboss-qa-internal@redhat.com or #jbossqa
Checkout trunk.
build/build.sh
testsuite/build.sh jboss-minimal-tests

The issue doesn't occur on physical machines as well jrockit is not affected.

If that could be of any help I've found two issues with java.lang.System not found and gcj.
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6371479
http://www.linuxhelpforum.com/showthread.php?t=809687

2 server trace logs attached. Part of log see below:
2007-07-31 05:04:11,222 DEBUG [org.jboss.deployers.plugins.deployers.DeployersIm
pl] Fully Undeployed vfsfile:/qa/services/hudson/hudson_workspace/workspace/JBos
s_AS_Testsuite_HEAD-jdk15/src/build/output/jboss-5.0.0.Beta3/server/minimal/depl
oy/shutdown.sar
2007-07-31 05:04:11,223 TRACE [org.jboss.system.server.profileservice.hotdeploy.
HDScanner] End deployment scan
2007-07-31 05:04:11,223 TRACE [org.jboss.mx.loading.RepositoryClassLoader] loadC
lass org.jboss.mx.loading.UnifiedClassLoader3@fc9d2b

{ url=null ,addedOrder=3} na
me=java.lang.System, loadClassDepth=0
2007-07-31 05:04:11,223 TRACE [org.jboss.mx.loading.UnifiedClassLoader] loadClas
sImpl, name=java.lang.System, resolve=false
2007-07-31 05:04:11,223 TRACE [org.jboss.mx.loading.RepositoryClassLoader] loadC
lass org.jboss.mx.loading.UnifiedClassLoader3@fc9d2b{ url=null ,addedOrder=3}

na
me=java.lang.System, loadClassDepth=1
2007-07-31 05:04:11,223 TRACE [org.jboss.mx.loading.UnifiedClassLoader] loadClas
sImpl, name=java.lang.System, resolve=false
2007-07-31 05:04:11,223 TRACE [org.jboss.mx.loading.RepositoryClassLoader] loadC
lass org.jboss.mx.loading.UnifiedClassLoader3@fc9d2b

{ url=null ,addedOrder=3} na
me=java.lang.System not found
2007-07-31 05:04:11,224 TRACE [org.jboss.mx.loading.RepositoryClassLoader] loadC
lass org.jboss.mx.loading.UnifiedClassLoader3@fc9d2b{ url=null ,addedOrder=3}

na
me=java.lang.System not found
2007-07-31 05:04:11,225 ERROR [STDERR] Exception in thread "ExitOnShutdown"
2007-07-31 05:04:11,226 ERROR [STDERR] java.lang.NoClassDefFoundError: java/lang
/System
2007-07-31 05:04:11,226 ERROR [STDERR] at org.jboss.test.jmx.shutdown.ExitOnShu
tdown$1.run(ExitOnShutdown.java:52)
2007-07-31 05:04:11,227 ERROR [STDERR] at java.lang.Thread.run(Thread.java:595)