The following test failed in the JDK15 CI:

java/net/Inet4Address/PingThis.java

Here's a snippet from the log file:

#section:main
----------messages:(4/210)----------
command: main -Djava.net.preferIPv4Stack=true PingThis
reason: User specified action: run main/othervm -Djava.net.preferIPv4Stack=true PingThis
Mode: othervm [/othervm specified]
elapsed time (seconds): 3.388
----------configuration:(0/0)----------
----------System.out:(3/69)----------
The target ip is 0.0.0.0
the target is reachable: false
Test failed
----------System.err:(13/822)----------
java.lang.Exception: address 0.0.0.0 can not be reachable!
at PingThis.main(PingThis.java:72)
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.Exception: address 0.0.0.0 can not be reachable!
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.lang.Exception: address 0.0.0.0 can not be reachable!
----------rerun:(38/4706)*----------


Much older similar, intermittent failure with the same test on macOSX:

    JDK-8074573 PingThis.java fails intermittently with "java.net.SocketException: No route to host"