The following test failed in the JDK16 CI:

gc/g1/TestHumongousConcurrentStartUndo.java

Here's a snippet from the log file:

[0.356s][info][gc,heap,exit ] Heap
[0.356s][info][gc,heap,exit ] garbage-first heap total 229376K, used 1694K [0x00000000f2000000, 0x0000000100000000)
[0.356s][info][gc,heap,exit ] region size 1024K, 2 young (2048K), 1 survivors (1024K)
[0.356s][info][gc,heap,exit ] Metaspace used 5074K, capacity 5151K, committed 5376K, reserved 1056768K
[0.356s][info][gc,heap,exit ] class space used 414K, capacity 434K, committed 512K, reserved 1048576K
];
 stderr: []
 exitValue = 0

java.lang.RuntimeException: 'Concurrent Mark Cycle' missing from stdout/stderr

at jdk.test.lib.process.OutputAnalyzer.shouldContain(OutputAnalyzer.java:189)
at gc.g1.TestHumongousConcurrentStartUndo.main(TestHumongousConcurrentStartUndo.java:77)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)
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.RuntimeException: 'Concurrent Mark Cycle' missing from stdout/stderr