After JDK-8331142 was integrated, the test/jdk/javax/swing/plaf/basic/BasicDirectoryModel/LoaderThreadCount.java test has failed twice in CI with different errors:

macos-aarch64:
Exception in Test Runner: class java.lang.RuntimeException: Invalid results: no loader threads detected
java.lang.RuntimeException: Invalid results: no loader threads detected
        at LoaderThreadCount.runTest(LoaderThreadCount.java:148)
        at LoaderThreadCount.wrapper(LoaderThreadCount.java:107)
        at java.base/java.lang.Thread.run(Thread.java:1575)

That is the background thread is not found in any of the 20 snapshots of live threads taken.

macos-x64:
Number of snapshots: 17
Number of snapshots where number of loader threads:
  = 1: 15
  = 2: 1
  > 2: 1
Exception in Test Runner: class java.lang.RuntimeException: Detected 1 snapshots with several loading threads
java.lang.RuntimeException: Detected 1 snapshots with several loading threads
        at LoaderThreadCount.runTest(LoaderThreadCount.java:167)
        at LoaderThreadCount.wrapper(LoaderThreadCount.java:107)
        at java.base/java.lang.Thread.run(Thread.java:1575)

The first condition is unexpected.

The second condition is unexpected either, yet its nature is different. It may still be possible that a thread is interrupted but isn't terminated yet. Similar to the 2 threads in the snapshots.