Why does AudioSystem.getMixerInfo() return different results under sbt vs Scala?

Question

After a lot of problem isolation, I got this snippet:

object Snippet  {
    def main(args: Array[String]): Unit = {
        println(\"Snip demo:: \"+ util.Proper         


        

Answer 1

This is a classloader issue. javax.sound does NOT like having the context classloader be anything other than the system classloader. This fixes it for me locally:

object Snippet  {
    def main(args: Array[String]): Unit = {
        println("Snip demo:: "+ util.Properties.versionString)
        println(" jvm "+System.getProperty("java.version"))
        import javax.sound.sampled._
        val cl = classOf[javax.sound.sampled.AudioSystem].getClassLoader
        val old = Thread.currentThread.getContextClassLoader
        try {
          Thread.currentThread.setContextClassLoader(cl)
          val mixers : Array[Mixer.Info] = javax.sound.sampled.AudioSystem.getMixerInfo()
          println(" Numer of mixers: "+ mixers.size)
          for (mi : Mixer.Info <- mixers ) { 
            println("mixer info "+mi.getName) 
          }
       } finally Thread.currentThread.setContextClassLoader(old) 
    }
}

And the output:

> run
[info] Compiling 1 Scala source to /home/jsuereth/projects/sbt/diagnose/sound-issues/target/scala-2.10/classes...
[info] Running Snippet 
Snip demo:: version 2.10.4
 jvm 1.7.0_55
 Numer of mixers: 9
mixer info default [default]
mixer info PCH [plughw:0,0]
mixer info NVidia [plughw:1,3]
mixer info NVidia [plughw:1,7]
mixer info NVidia [plughw:1,8]
mixer info NVidia [plughw:1,9]
mixer info Port PCH [hw:0]
mixer info Port NVidia [hw:1]
mixer info Port Unknown Name
[success] Total time: 2 s, completed Aug 1, 2014 11:00:03 AM
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