I've seen this failure during nightly testing:

#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/tmp/jprt/P1/B/214418.ap31282/source/src/share/vm/utilities/growableArray.hpp:186), pid=31966, tid=4087872400
# Error: assert(0 <= i && i < _len,"illegal index")
#
# JRE version: 7.0-b86
# Java VM: OpenJDK Client VM (17.0-b10-2010-03-22-214418.ap31282.hotspot-g1-push-fastdebug mixed mode linux-x86 )
# If you would like to submit a bug report, please visit:
# http://java.sun.com/webapps/bugreport/crash.jsp
#

This is the stack trace:

Stack: [0xf3a00000,0xf3a80000], sp=0xf3a7ebf0, free space=1faf3a7ec68k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x699ca5];; _ZN7VMError6reportEP12outputStream+0x13f5
V [libjvm.so+0x699f34];; _ZN7VMError14report_and_dieEv+0x194
V [libjvm.so+0x2b3105];; _Z24report_assertion_failurePKciS0_+0x65
V [libjvm.so+0x2f862f];; _ZN15G1CollectedHeap9region_atEj+0x2f
V [libjvm.so+0x34dbcb];; _ZN16HeapRegionRemSet5clearEv+0x8b
V [libjvm.so+0x26f2bd];; _ZN14ConcurrentMark15completeCleanupEv+0xad
V [libjvm.so+0x2a15e2];; _ZN20ConcurrentMarkThread3runEv+0x7c2
V [libjvm.so+0x562469];; _ZL10java_startP6Thread+0xf9
C [libpthread.so.0+0x63c0]