The following test failed in the JDK15 CI:

sun/management/jmxremote/startstop/JMXStartStopTest.java

Here's a snippet from failure of test_13:

**** Test thirteen ****
Command line: [/scratch/mesos/jib-master/install/jdk-15+15-610/macosx-x64-debug.jdk/jdk-15/fastdebug/bin/java -cp /scratch/mesos/slaves/b0d836b1-c68c-4dbd-8b78-5085890ddd4c-S1076/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/237184e6-7e4f-4bac-a71c-e2d12979fa4f/runs/bac8bb58-d3df-4ecf-b32e-5c230a783366/testoutput/test-support/jtreg_open_test_jdk_jdk_management/classes/0/sun/management/jmxremote/startstop/JMXStartStopTest.d:/scratch/mesos/jib-master/install/jdk-15+15-610/src.full/open/test/jdk/sun/management/jmxremote/startstop:/scratch/mesos/slaves/b0d836b1-c68c-4dbd-8b78-5085890ddd4c-S1076/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/237184e6-7e4f-4bac-a71c-e2d12979fa4f/runs/bac8bb58-d3df-4ecf-b32e-5c230a783366/testoutput/test-support/jtreg_open_test_jdk_jdk_management/classes/0/test/lib:/scratch/mesos/jib-master/install/jdk-15+15-610/src.full/open/test/lib:/scratch/mesos/jib-master/install/jtreg/5.0/b01/bundles/jtreg_bin-5.0.zip/jtreg/lib/javatest.jar:/scratch/mesos/jib-master/install/jtreg/5.0/b01/bundles/jtreg_bin-5.0.zip/jtreg/lib/jtreg.jar -cp /scratch/mesos/slaves/b0d836b1-c68c-4dbd-8b78-5085890ddd4c-S1076/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/237184e6-7e4f-4bac-a71c-e2d12979fa4f/runs/bac8bb58-d3df-4ecf-b32e-5c230a783366/testoutput/test-support/jtreg_open_test_jdk_jdk_management/classes/0/sun/management/jmxremote/startstop/JMXStartStopTest.d:/scratch/mesos/slaves/b0d836b1-c68c-4dbd-8b78-5085890ddd4c-S1076/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/237184e6-7e4f-4bac-a71c-e2d12979fa4f/runs/bac8bb58-d3df-4ecf-b32e-5c230a783366/testoutput/test-support/jtreg_open_test_jdk_jdk_management/classes/0/test/lib -XX:+UsePerfData -Dcom.sun.management.jmxremote.port=55615 -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=true TestApp ]
[TestApp{test_13}]:/scratch/mesos/jib-master/install/jdk-15+15-610/macosx-x64-debug.jdk/jdk-15/fastdebug/bin/java -cp /scratch/mesos/slaves/b0d836b1-c68c-4dbd-8b78-5085890ddd4c-S1076/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/237184e6-7e4f-4bac-a71c-e2d12979fa4f/runs/bac8bb58-d3df-4ecf-b32e-5c230a783366/testoutput/test-support/jtreg_open_test_jdk_jdk_management/classes/0/sun/management/jmxremote/startstop/JMXStartStopTest.d:/scratch/mesos/jib-master/install/jdk-15+15-610/src.full/open/test/jdk/sun/management/jmxremote/startstop:/scratch/mesos/slaves/b0d836b1-c68c-4dbd-8b78-5085890ddd4c-S1076/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/237184e6-7e4f-4bac-a71c-e2d12979fa4f/runs/bac8bb58-d3df-4ecf-b32e-5c230a783366/testoutput/test-support/jtreg_open_test_jdk_jdk_management/classes/0/test/lib:/scratch/mesos/jib-master/install/jdk-15+15-610/src.full/open/test/lib:/scratch/mesos/jib-master/install/jtreg/5.0/b01/bundles/jtreg_bin-5.0.zip/jtreg/lib/javatest.jar:/scratch/mesos/jib-master/install/jtreg/5.0/b01/bundles/jtreg_bin-5.0.zip/jtreg/lib/jtreg.jar -cp /scratch/mesos/slaves/b0d836b1-c68c-4dbd-8b78-5085890ddd4c-S1076/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/237184e6-7e4f-4bac-a71c-e2d12979fa4f/runs/bac8bb58-d3df-4ecf-b32e-5c230a783366/testoutput/test-support/jtreg_open_test_jdk_jdk_management/classes/0/sun/management/jmxremote/startstop/JMXStartStopTest.d:/scratch/mesos/slaves/b0d836b1-c68c-4dbd-8b78-5085890ddd4c-S1076/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/237184e6-7e4f-4bac-a71c-e2d12979fa4f/runs/bac8bb58-d3df-4ecf-b32e-5c230a783366/testoutput/test-support/jtreg_open_test_jdk_jdk_management/classes/0/test/lib -XX:+UsePerfData -Dcom.sun.management.jmxremote.port=55615 -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=true TestApp
[TestApp{test_13}] main enter
[jcmd]:/scratch/mesos/jib-master/install/jdk-15+15-610/macosx-x64-debug.jdk/jdk-15/fastdebug/bin/jcmd TestApp ManagementAgent.stop
[jcmd] 39412:
[jcmd] Command executed successfully
[jcmd]:/scratch/mesos/jib-master/install/jdk-15+15-610/macosx-x64-debug.jdk/jdk-15/fastdebug/bin/jcmd TestApp ManagementAgent.start jmxremote.ssl=false jmxremote.port=55615
[jcmd] 39412:
[jcmd] Command executed successfully
[TestApp{test_13}] read: 0
[TestApp{test_13}] main exit
(took 7477ms)

**** Test fourteen ****
<snip>

test_13 failed
java.lang.reflect.InvocationTargetException
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at JMXStartStopTest.main(JMXStartStopTest.java:289)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
at java.base/java.lang.Thread.run(Thread.java:832)
Caused by: java.rmi.NoSuchObjectException: no such object in table
at java.rmi/sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemoteCall.java:303)
at java.rmi/sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:279)
at java.rmi/sun.rmi.server.UnicastRef.invoke(UnicastRef.java:380)
at java.rmi/sun.rmi.registry.RegistryImpl_Stub.list(RegistryImpl_Stub.java:91)
at JMXStartStopTest.doTestConnect(JMXStartStopTest.java:195)
at JMXStartStopTest.testConnect(JMXStartStopTest.java:169)
at JMXStartStopTest.testConnect(JMXStartStopTest.java:160)
at JMXStartStopTest.test_13(JMXStartStopTest.java:809)
... 11 more
java.lang.Error
at JMXStartStopTest.main(JMXStartStopTest.java:315)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
at java.base/java.lang.Thread.run(Thread.java:832)

JavaTest Message: Test threw exception: java.lang.Error
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.lang.Error
----------rerun:(39/5919)*----------

This test executes a number of subtests some of which are
expected to PASS because they are checking for an error.
This means that System.err will contain error messages
that are not related to the actual failure mode for this test
run which happened in test_13.