The following test failed in the JDK20 CI:

java/nio/channels/SocketChannel/VectorIO.java

Here's a snippet from the log file:

#section:main
----------messages:(5/130)----------
command: main VectorIO
reason: User specified action: run main VectorIO
Mode: agentvm
Agent id: 12
elapsed time (seconds): 8.175
----------configuration:(18/2607)----------

<snip>

----------System.err:(22/1054)----------
Length 1
accept() succeeded
Length 15
java.lang.Exception: Server 15: Timed out
at TestThread.finish(TestThread.java:67)
at VectorIO.runTest(VectorIO.java:65)
at VectorIO.main(VectorIO.java:56)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:578)
at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:312)
at java.base/java.lang.Thread.run(Thread.java:1589)
java.lang.Exception: Failed: Length = 15
at VectorIO.runTest(VectorIO.java:66)
at VectorIO.main(VectorIO.java:56)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:578)
at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:312)
at java.base/java.lang.Thread.run(Thread.java:1589)

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

----------System.out:(1/47)----------
Seed from RandomFactory = -961623379516143860L
result: Failed. Execution failed: `main' threw exception: java.lang.Exception: Failed: Length = 15


test result: Failed. Execution failed: `main' threw exception: java.lang.Exception: Failed: Length = 15


There is an older bug that was closed as "Cannot Reproduce":

    JDK-8177801 (ch) java/nio/channels/SocketChannel/VectorIO.java fails intermittently

and that bug requested that a new bug be filed if this failure mode
happened again.