The javax.sound jtreg tests do not have the headful keyword so are eligible to be run on systems where the test environment may be a daemon thread without access to sound devices, or the even there may be no sound devices in a VM.

It appears that the result is that tests are bailing and reporting a pass in such situations eg this run of javax/sound/midi/Synthesizer/AsynchronousMidiChannel.java on a Windows VM :
====

command: main AsynchronousMidiChannel
reason: Assumed action based on file name: run main AsynchronousMidiChannel
Mode: othervm
Additional options from @modules: --add-modules java.desktop
elapsed time (seconds): 0.752
----------configuration:(3/43)----------
Boot Layer
  add modules: java.desktop

----------System.out:(2/74)----------
Got synth: com.sun.media.sound.SoftSynthesizer@767f90bd
could not test.
----------System.err:(2/115)----------
MidiUnavailableException was thrown: javax.sound.midi.MidiUnavailableException: Can not open line
STATUS:Passed.

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There needs to be a (tedious) audit of these tests to see which ones need
 @key headful
which would mean "this test actually needs the sound device" just like many UI tests really need a framebuffer, since the resources are "usually" equivalent
I think
@ key sound
would be useful too even if we don't use it (yet) just to be available.
The sound tests are neatly partioned into the javax/sound directory so it could be argued it is implied but it would still be better to have it explicit because we could also have a VM situation where we have a virtual framebuffer but no virtual sound