RFR: 8356049: Need a simple way to play back a sound clip [v6]

[Phil Race]

On Sat, 24 May 2025 03:22:41 GMT, Sergey Bylokhov <serb at openjdk.org> wrote:

> > For me, once the end of "main()" is reached the VM exits. Even if a sound is playing and looping.
> > And even then, are you suggesting this would block System.exit() ?
> > Where have you actually seen this problem or why are you sure it is a problem ?
> 
> It does not prevent the application from exiting via `System.exit()`, but it does prevent it from exiting naturally when the main method completes. This is consistent with how AWT behaves (as [documented here](https://github.com/openjdk/jdk/blob/fdda7661906eab63d939e9f482449e21cc143c8f/src/java.desktop/share/classes/java/awt/doc-files/AWTThreadIssues.html#L108)): the application should dispose of all Windows/Frames to be shutdown.
> 
> Similarly, this new API appears to follow the same logic: all playable clips must be stopped, otherwise the application will keep running indefinitely.
> 
> I tested this behavior on macOS using [this MIDI file](https://en.wikipedia.org/wiki/File:MIDI_sample.mid?oldformat=true).
> 
> ```
> import java.io.File;
> 
> import javax.sound.SoundClip;
> 
> public final class TestClip {
>     public static void main(String[] args) throws Exception {
>         SoundClip soundClip = SoundClip.createSoundClip(new File("MIDI_sample.mid"));
>         soundClip.loop();
>         System.out.println("end main");
>     }
> }
> ```

So it seems it varies depending on content-type.

This midi case creates a DataPusher which creates a non-daemon thread.

                pushThread = JSSecurityManager.createThread(this,
                                                            "DataPusher", // name
                                                            false,  // daemon <<<<<<<<<<<<<<
                                                            -1,    // priority
                                                            true); // doStart


DataPusher is only used by JavaAudioSoundClip although that is used by a few content handlers as well as the *Clip APIs.
Other than this only MidiInDevice creates a non-daemon thread and that won't be used by SoundClip

So I am sure it is possible to pass in a parameter to tell DataPusher it should use a daemon thread for this case - leaving other cases unaffected - and then we'd consistently terminate and can remove all the words in the javadoc about this.

Take a look at the commit I am pushing now - updates the implementation but not (yet) revising the javadoc.

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PR Comment: https://git.openjdk.org/jdk/pull/24991#issuecomment-2906952672