How to run a Scala application in a jar file while setting the classpath

I don’t know why, but without digging into it more, all I can say right now is that I can’t use the Java Sound API from within SBT. Whenever I try running sbt run, I keep getting the following error message, even though I know that my app and sound file work fine when I package my Java application normally:

javax.sound.sampled.UnsupportedAudioFileException: could not get audio input stream from input file

As part of the debugging process I created a little shell script named that contained these two lines:

sbt package
scala -classpath "lib/littlelogger-0.1.jar:target/scala-2.10/typewriter_2.10-1.0.jar" com.valleyprogramming.typewriter.GainTester

The first line packages my Scala source code into a Jar file, and the second line sets my classpath while running my application (GainTester) with the Scala interpreter. For some reason this shell script works fine, but trying to run the code from within SBT yields the error I showed initially.

While that problem remains a mystery, if you ever wanted to see how to run a Scala Jar file while also setting the classpath, I hope that last line is helpful.