Cannot save generated midi java.lang.NoClassDefFoundError: Failed resolution of: Ljp/kshoji/javax/sound/midi/MidiSystem;

[mkutr]

Hi! I am trying to use the Jfugue on Android, but I am getting this error:

java.lang.NoClassDefFoundError: Failed resolution of: Ljp/kshoji/javax/sound/midi/MidiSystem;
at org.jfugue.player.SequencerManager.getDefaultSequencer(SequencerManager.java:55)
at org.jfugue.player.SequencerManager.<init>(SequencerManager.java:50)
at org.jfugue.player.SequencerManager.getInstance(SequencerManager.java:41)
at org.jfugue.player.ManagedPlayer.<init>(ManagedPlayer.java:47)
at org.jfugue.player.Player.<init>(Player.java:46)
at org.jfugue.midi.MidiFileManager.savePatternToMidi(MidiFileManager.java:53)
at org.jfugue.midi.MidiFileManager.savePatternToMidi(MidiFileManager.java:58)
at com.avister.midiGeneration.GenerateMidiActivity.dubSave(GenerateMidiActivity.kt:52)
at com.avister.ml.models.MusicGeneratorAndroidTest$dubSaveTest$1.perform(MusicGeneratorAndroidTest.kt:141)
at com.avister.ml.models.MusicGeneratorAndroidTest$dubSaveTest$1.perform(MusicGeneratorAndroidTest.kt:18)
at androidx.test.core.app.ActivityScenario.lambda$onActivity$2$ActivityScenario(ActivityScenario.java:660)
at androidx.test.core.app.ActivityScenario$$ExternalSyntheticLambda2.run(Unknown Source:4)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:462)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at android.app.Instrumentation$SyncRunnable.run(Instrumentation.java:2223)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
Caused by: java.lang.ClassNotFoundException: Didn't find class "jp.kshoji.javax.sound.midi.MidiSystem" on path: DexPathList[[zip file "/system/framework/android.test.runner.jar", zip file "/system/framework/android.test.mock.jar", zip file "/system/framework/android.test.base.jar", zip file "/data/app/~~lil1u2Nb8-ocLGw0F8dAbw==/com.avister.test-F5TBrSomZjMeER7Y26_viQ==/base.apk", zip file "/data/app/~~h9pnhGV0TWqabygf7I8F7Q==/com.avister-zQJ2i_8pkzzeqXPzP3hGLg==/base.apk"],nativeLibraryDirectories=[/data/app/~~lil1u2Nb8-ocLGw0F8dAbw==/com.avister.test-F5TBrSomZjMeER7Y26_viQ==/lib/x86, /data/app/~~h9pnhGV0TWqabygf7I8F7Q==/com.avister-zQJ2i_8pkzzeqXPzP3hGLg==/lib/x86, /data/app/~~lil1u2Nb8-ocLGw0F8dAbw==/com.avister.test-F5TBrSomZjMeER7Y26_viQ==/base.apk!/lib/x86, /data/app/~~h9pnhGV0TWqabygf7I8F7Q==/com.avister-zQJ2i_8pkzzeqXPzP3hGLg==/base.apk!/lib/x86, /system/lib, /system_ext/lib]]
at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:207)
at java.lang.ClassLoader.loadClass(ClassLoader.java:379)
at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
... 22 more

When trying to perform this test:

internal class MusicGeneratorAndroidTest {

    @get:Rule
    val activityTestRule = ActivityScenarioRule(GenerateMidiActivity::class.java)

    @Test
    fun exampleSaveTest() {
        activityTestRule.scenario.onActivity {
            it.exampleSave()
        }
    }
}

class GenerateMidiActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_generate_midi)
    }

    fun exampleSave() {
        val cw = ContextWrapper(applicationContext)
        val directory = cw.getExternalFilesDir(Environment.DIRECTORY_MUSIC)
        val pattern: Pattern = Pattern("C4")
        val file = File(directory, "test.midi")
        MidiFileManager.savePatternToMidi(pattern, file)
    }
}

What may be the cause and how to fix this?