The following test failed in the JDK16 CI:

com/sun/jdi/JdwpAttachTest.java

Here's a snippet from the log file:

Test: listen on '0:0:0:0:0:0:0:1', attach to ''
[ 21.763] Starting listening at 0:0:0:0:0:0:0:1
[ 21.764] Listening port: 52857
[ 21.764] Attaching to
Command line: ['/opt/mach5/mesos/work_dir/jib-master/install/jdk-16+19-928/linux-x64-debug.jdk/jdk-16/fastdebug/bin/java' '-Xmx512m' '-XX:MaxRAMPercentage=6' '-Djava.io.tmpdir=/opt/mach5/mesos/work_dir/slaves/4076d11c-c6ed-4d07-84c1-4ab8d55cd975-S108713/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/db2c7401-659d-43c9-8c63-b62357a559fd/runs/f6b24f02-1a93-4605-916e-a62ba35ed39e/testoutput/test-support/jtreg_open_test_jdk_jdk_jdi/tmp' '-ea' '-esa' '-XX:+CreateCoredumpOnCrash' '-XX:+UseSerialGC' '-agentlib:jdwp=transport=dt_socket,address=:52857,server=n,suspend=n' '-cp' '/opt/mach5/mesos/work_dir/slaves/4076d11c-c6ed-4d07-84c1-4ab8d55cd975-S108713/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/db2c7401-659d-43c9-8c63-b62357a559fd/runs/f6b24f02-1a93-4605-916e-a62ba35ed39e/testoutput/test-support/jtreg_open_test_jdk_jdk_jdi/classes/0/com/sun/jdi/JdwpAttachTest.d:/opt/mach5/mesos/work_dir/slaves/4076d11c-c6ed-4d07-84c1-4ab8d55cd975-S108713/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/db2c7401-659d-43c9-8c63-b62357a559fd/runs/f6b24f02-1a93-4605-916e-a62ba35ed39e/testoutput/test-support/jtreg_open_test_jdk_jdk_jdi/classes/0/test/lib' 'jdk.test.lib.apps.LingeredApp' '95e8284b-c338-4fda-af15-5be4ec1286b7.lck']
LingeredApp failed to start: java.io.IOException: App exited unexpectedly with 2
 LingeredApp stdout: [];
 LingeredApp stderr: [ERROR: transport error 202: handshake failed - received >< - expected >JDWP-Handshake<
ERROR: JDWP Transport dt_socket failed to initialize, TRANSPORT_INIT(510)
JDWP exit error AGENT_ERROR_TRANSPORT_INIT(197): No transports initialized [/opt/mach5/mesos/work_dir/slaves/4076d11c-c6ed-4d07-84c1-4ab8d55cd975-S108840/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/0042995f-21da-469b-9a5a-d7f2d12c8960/runs/18f14ea9-2493-4027-83af-f99088d34ddf/workspace/open/src/jdk.jdwp.agent/share/native/libjdwp/debugInit.c:734]
]
 LingeredApp exitValue = 2
----------System.err:(14/937)----------
java.lang.RuntimeException: ERROR: LingeredApp.startApp was able to attach
at JdwpAttachTest.attachTest(JdwpAttachTest.java:136)
at JdwpAttachTest.main(JdwpAttachTest.java:88)
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: ERROR: LingeredApp.startApp was able to attach
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.lang.RuntimeException: ERROR: LingeredApp.startApp was able to attach
----------rerun:(41/6743)*----------