Audio not playing through Java on Raspberry Pi

Question

The issue

I'm trying to play sound on a Raspberry Pi 3 B+ through Java, but it doesn't work. I have

1. Written code (shown below) in IntelliJ, and confirmed that it works on Windows 10.
2. Connected speakers to my Raspberry Pi through aux and
   • Used sudo raspi-config to set audio to "headphones" (the only option).
   • Confirmed they work with aplay my-file.wav.
3. Attempted to run my code (through Gradle) with gradle run in the project directory. It displays the text "Playing audio" as expected, but no audio plays.
4. Tried the advice in this answer and this one and this forum (hence my audio testing above), all to no avail.

My entire code

import javax.sound.sampled.*;
import java.io.File;
import java.io.IOException;
public class Main {
 public static void main(String[] args) throws UnsupportedAudioFileException, IOException, LineUnavailableException, InterruptedException {
 File file = new File("my-file.wav");
 AudioInputStream audioStream = AudioSystem.getAudioInputStream(file.getAbsoluteFile());
 Clip clip = AudioSystem.getClip();
 clip.open(audioStream);
 System.out.println("Playing audio");
 clip.start();
 Thread.sleep(10000);
 }
}

Other info

I'm connecting to my Pi over SSH from Windows. My java --version is

openjdk 11.0.12 2021年07月20日
OpenJDK Runtime Environment (build 11.0.12+7-post-Raspbian-2deb10u1)
OpenJDK Server VM (build 11.0.12+7-post-Raspbian-2deb10u1, mixed mode)

My gradle --version is Gradle 6.8.3. I'm using Gradle because the real project I'm working on requires it (this one is obviously just a demo).

I'm interested in any solution whatsoever to use Java to play sound. Is there a way to simply have Java call another bit of code that does work?

• prunge: Maybe related: stackoverflow.com/questions/30377129/…

Answer 1

I found a workaround that works for me: replacing all the lines that create and start the AudioInputStream and Clip with this one line:

Runtime.getRuntime().exec("aplay my-file.wav");

Note: I have intentionally not marked this answer correct, because it does not solve the issue with AudioInputStream. It simply sidesteps the problem, by passing the issue of playing audio to the aplay command in terminal. Thus, it is not a solution, but it might nonetheless be helpful to someone who just wants to play some sound with Java on a pi, no matter how hacky the approach.

Interestingly, I also found that this breaks for any file path with spaces, and I have absolutely no idea why. I tried enclosing the path in single quotes and double quotes, and escaping spaces with backslashes, and all of those together. Nothing worked. Here's a related question without a definitive answer.