The following test failed in the an adhoc Mach5 job set:

vmTestbase/nsk/jdb/repeat/repeat001/repeat001.java

Here's a snippet from the log file:

#section:main
----------messages:(4/1765)----------
command: main nsk.jdb.repeat.repeat001.repeat001 -arch=linux-x64 -waittime=5 -debugee.vmkind=java -transport.address=dynamic -jdb=/opt/mach5/mesos/work_dir/jib-master/install/2021-10-30-1448588.daniel.daugherty.8273967_for_jdk18.git/linux-x64-debug.jdk/jdk-18/fastdebug/bin/jdb -jdb.option="-J-Duser.language=en -J-Duser.country=US" -java.options="-XX:MaxRAMPercentage=4.16667 -Djava.io.tmpdir=/opt/mach5/mesos/work_dir/slaves/ff806ead-2cac-495d-9cbc-62116f99bf14-S14051/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/0e320c3c-7a68-4dfc-a34b-a4efea83d66d/runs/b1e54477-7408-46d3-8b57-0f3c9fd27b35/testoutput/test-support/jtreg_open_test_hotspot_jtreg_vmTestbase_nsk_jdb/tmp -Xcomp -XX:+CreateCoredumpOnCrash -ea -esa -XX:CompileThreshold=100 -XX:+UnlockExperimentalVMOptions -server -XX:+TieredCompilation" -workdir=. -debugee.vmkeys="-XX:MaxRAMPercentage=4.16667 -Djava.io.tmpdir=/opt/mach5/mesos/work_dir/slaves/ff806ead-2cac-495d-9cbc-62116f99bf14-S14051/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/0e320c3c-7a68-4dfc-a34b-a4efea83d66d/runs/b1e54477-7408-46d3-8b57-0f3c9fd27b35/testoutput/test-support/jtreg_open_test_hotspot_jtreg_vmTestbase_nsk_jdb/tmp -Xcomp -XX:+CreateCoredumpOnCrash -ea -esa -XX:CompileThreshold=100 -XX:+UnlockExperimentalVMOptions -server -XX:+TieredCompilation"
reason: User specified action: run main/othervm nsk.jdb.repeat.repeat001.repeat001 -arch=${os.family}-${os.simpleArch} -waittime=5 -debugee.vmkind=java -transport.address=dynamic -jdb=${test.jdk}/bin/jdb -jdb.option="-J-Duser.language=en -J-Duser.country=US" -java.options="${test.vm.opts} ${test.java.opts}" -workdir=. -debugee.vmkeys="${test.vm.opts} ${test.java.opts}"
Mode: othervm [/othervm specified]
elapsed time (seconds): 118.17
----------configuration:(0/0)----------
----------System.out:(16/1545)----------
Launching process by array of args:
    args[0]: >/opt/mach5/mesos/work_dir/jib-master/install/2021-10-30-1448588.daniel.daugherty.8273967_for_jdk18.git/linux-x64-debug.jdk/jdk-18/fastdebug/bin/jdb<
    args[1]: >-J-XX:MaxRAMPercentage=4.16667<
    args[2]: >-J-Djava.io.tmpdir=/opt/mach5/mesos/work_dir/slaves/ff806ead-2cac-495d-9cbc-62116f99bf14-S14051/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/0e320c3c-7a68-4dfc-a34b-a4efea83d66d/runs/b1e54477-7408-46d3-8b57-0f3c9fd27b35/testoutput/test-support/jtreg_open_test_hotspot_jtreg_vmTestbase_nsk_jdb/tmp<
    args[3]: >-J-Xcomp<
    args[4]: >-J-XX:+CreateCoredumpOnCrash<
    args[5]: >-J-ea<
    args[6]: >-J-esa<
    args[7]: >-J-XX:CompileThreshold=100<
    args[8]: >-J-XX:+UnlockExperimentalVMOptions<
    args[9]: >-J-server<
    args[10]: >-J-XX:+TieredCompilation<
    args[11]: >-J-Duser.language=en<
    args[12]: >-J-Duser.country=US<
    args[13]: >-connect<
    args[14]: >com.sun.jdi.CommandLineLaunch:vmexec=java,options= "-XX:MaxRAMPercentage=4.16667" "-Djava.io.tmpdir=/opt/mach5/mesos/work_dir/slaves/ff806ead-2cac-495d-9cbc-62116f99bf14-S14051/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/0e320c3c-7a68-4dfc-a34b-a4efea83d66d/runs/b1e54477-7408-46d3-8b57-0f3c9fd27b35/testoutput/test-support/jtreg_open_test_hotspot_jtreg_vmTestbase_nsk_jdb/tmp" "-Xcomp" "-XX:+CreateCoredumpOnCrash" "-ea" "-esa" "-XX:CompileThreshold=100" "-XX:+UnlockExperimentalVMOptions" "-server" "-XX:+TieredCompilation",main=nsk.jdb.repeat.repeat001.repeat001a<
----------System.err:(15/875)----------
java.lang.AssertionError: Unexpected output
at nsk.jdb.repeat.repeat001.repeat001.runCasesNoCleanup(repeat001.java:142)
at nsk.jdb.repeat.repeat001.repeat001.runCases(repeat001.java:87)
at nsk.share.jdb.JdbTest.runTest(JdbTest.java:149)
at nsk.jdb.repeat.repeat001.repeat001.run(repeat001.java:77)
at nsk.jdb.repeat.repeat001.repeat001.main(repeat001.java:71)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:577)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
at java.base/java.lang.Thread.run(Thread.java:833)

JavaTest Message: Test threw exception: java.lang.AssertionError: Unexpected output
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.lang.AssertionError: Unexpected output
----------rerun:(42/10433)*----------


The test task's JVM args are:

-Xcomp -XX:+CreateCoredumpOnCrash -ea -esa -XX:CompileThreshold=100 -XX:+UnlockExperimentalVMOptions -server -XX:+TieredCompilation


The test is complaining about "Unexpected output"
but I'm not seeing any unexpected output in the log file.

This is a new test added by the following:

JDK-8271356 Modify jdb to treat an empty command as a repeat of the previous command