running many instances of jps concurrently produce strage output like:

8081 -- process information unavailable
8091 -- process information unavailable
8050 -- process information unavailable
8065 -- process information unavailable
8086 -- process information unavailable

This output can provoke failures in scripts that use jps output with grep and awk postprocessing. Output of jps shouldn't include any diagnostic messages, only discovered proccesses and requested information about them.
Please find the output below - with the suggested flags (-J-Djps.debug=true -J-Djps.printStackTrace=true) :
8120 -- process information unavailable
    8120 not found
sun.jvmstat.monitor.MonitorException: 8120 not found
    at sun.jvmstat.perfdata.monitor.protocol.local.PerfDataBuffer.<init>(PerfDataBuffer.java:66)
    at sun.jvmstat.perfdata.monitor.protocol.local.LocalMonitoredVm.<init>(LocalMonitoredVm.java:51)
    at sun.jvmstat.perfdata.monitor.protocol.local.MonitoredHostProvider.getMonitoredVm(MonitoredHostProvider.java:60)
    at sun.tools.jps.Jps.main(Jps.java:65)
Caused by: java.lang.IllegalArgumentException: Process not found
    at sun.misc.Perf.attach(Native Method)
    at sun.misc.Perf.attachImpl(Perf.java:253)
    at sun.misc.Perf.attach(Perf.java:183)
    at sun.jvmstat.perfdata.monitor.protocol.local.PerfDataBuffer.<init>(PerfDataBuffer.java:46)
    ... 3 more
=============================================================
Used the below script to reproduce/ get the above exception :
#!/bin/ksh

which java
java -version

i=0
while [ i -le 10 ]
do
    jps -J-Djps.debug=true -J-Djps.printStackTrace=true > jps${i}.log 2>&1 &
    i=`expr $i + 1`
done
=================================
At least one of the log files (out of 10 above) did have this exception.