I have experienced this a couple of times, but I don't have a strong handle on the cause. I am unable to repeat it at will (yet). I will keep trying, but would appreaciate some pointers.

17:57:26.228 0x181d90b00 j9mm.141 * ** ASSERTION FAILED ** at ParallelScavenger.cpp:1887: ((false))
JVMDUMP039I Processing dump event "traceassert", detail "" at 2012/12/14 17:57:26 - please wait.
JVMDUMP032I JVM requested System dump using '/rns/lightStreamer/bin/ibmi/core.20121214.175726.27483.0001.dmp' in response to an ev
JVMDUMP010I System dump written to /rns/lightStreamer/bin/ibmi/core.20121214.175726.27483.0001.dmp
JVMDUMP032I JVM requested Java dump using '/rns/lightStreamer/bin/ibmi/javacore.20121214.175726.27483.0002.txt' in response to an
JVMDUMP012E Error in Java dump: /rns/lightStreamer/bin/ibmi/javacore.20121214.175726.27483.0002.txt
JVMDUMP032I JVM requested Snap dump using '/rns/lightStreamer/bin/ibmi/Snap.20121214.175726.27483.0003.trc' in response to an even
JVMDUMP010I Snap dump written to /rns/lightStreamer/bin/ibmi/Snap.20121214.175726.27483.0003.trc
JVMDUMP013I Processed dump event "traceassert", detail "".