The following test failed in the JDK26 CI:

com/sun/net/httpserver/Test12.java

Here's a snippet from the log file:

#section:main
----------messages:(8/393)----------
command: main -Djava.net.preferIPv6Addresses=true Test12
reason: User specified action: run main/othervm -Djava.net.preferIPv6Addresses=true Test12
started: Fri Jun 13 19:26:51 UTC 2025
Mode: othervm [/othervm specified]
Additional options from @modules: --add-modules jdk.httpserver,java.logging
Process id: 29576
finished: Fri Jun 13 19:26:54 UTC 2025
elapsed time (seconds): 2.965
----------configuration:(3/58)----------
Boot Layer
  add modules: jdk.httpserver java.logging

----------System.out:(1/12)----------
Test12: OK
----------System.err:(17/1792)*----------
java.nio.file.FileSystemException: C:\\sb\\prod\\1749842502\\testoutput\\test-support\\jtreg_open_test_jdk_tier2_part3\\scratch\\1\\com.sun.net.httpserver-Test12-2659162053669711980.tmp: The process cannot access the file because it is being used by another process
at java.base/sun.nio.fs.WindowsException.translateToIOException(WindowsException.java:92)
at java.base/sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:103)
at java.base/sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:108)
at java.base/sun.nio.fs.WindowsFileSystemProvider.implDelete(WindowsFileSystemProvider.java:269)
at java.base/sun.nio.fs.AbstractFileSystemProvider.delete(AbstractFileSystemProvider.java:105)
at java.base/java.nio.file.Files.delete(Files.java:1052)
at Test12.main(Test12.java:113)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:565)
at com.sun.javatest.regtest.agent.MainWrapper$MainTask.run(MainWrapper.java:138)
at java.base/java.lang.Thread.run(Thread.java:1474)

JavaTest Message: Test threw exception: java.nio.file.FileSystemException: C:\\sb\\prod\\1749842502\\testoutput\\test-support\\jtreg_open_test_jdk_tier2_part3\\scratch\\1\\com.sun.net.httpserver-Test12-2659162053669711980.tmp: The process cannot access the file because it is being used by another process
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.nio.file.FileSystemException: C:\\sb\\prod\\1749842502\\testoutput\\test-support\\jtreg_open_test_jdk_tier2_part3\\scratch\\1\\com.sun.net.httpserver-Test12-2659162053669711980.tmp: The process cannot access the file because it is being used by another process
----------rerun:(47/6076)*----------

This error message indicates a temp file race:

java.nio.file.FileSystemException: C:\\sb\\prod\\1749842502\\testoutput\\test-support\\jtreg_open_test_jdk_tier2_part3\\scratch\\1\\com.sun.net.httpserver-Test12-2659162053669711980.tmp: The process cannot access the file because it is being used by another process