Web demo/Heroku + Java app not working

[samarutuk]

Hi Alexander,
the web demo/Heroku displays "Application error" and the Java app (aaba-1.1.jar) displays the following error message:

java -jar aaba-1.1.jar -o test.abc ah-vous-diraije-maman.abc
Using default configuration.
Reading melody and chords from: ah-vous-diraije-maman.abc
Writing arrangement to: test.abc

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
        at java.base/jdk.internal.util.Preconditions$1.apply(Preconditions.java:55)
        at java.base/jdk.internal.util.Preconditions$1.apply(Preconditions.java:52)
        at java.base/jdk.internal.util.Preconditions$4.apply(Preconditions.java:213)
        at java.base/jdk.internal.util.Preconditions$4.apply(Preconditions.java:210)
        at java.base/jdk.internal.util.Preconditions.outOfBounds(Preconditions.java:98)
        at java.base/jdk.internal.util.Preconditions.outOfBoundsCheckIndex(Preconditions.java:106)
        at java.base/jdk.internal.util.Preconditions.checkIndex(Preconditions.java:302)
        at java.base/java.lang.String.checkIndex(String.java:4832)
        at java.base/java.lang.StringLatin1.charAt(StringLatin1.java:46)
        at java.base/java.lang.String.charAt(String.java:1555)
        at de.saar.coli.arranger.abc.AbcParser.parseAbcNote(AbcParser.java:119)
        at de.saar.coli.arranger.abc.AbcParser.read(AbcParser.java:96)
        at de.saar.coli.arranger.Arrange.main(Arrange.java:59)

I tried with several (as simple as possible) abc files that I had downloaded from abcnotation.com, because I wasn't sure if my musicxml to abc converted files were ok. However, the error seems to be due to something slightly different.

The following Java version is installed on my system:
java version "21.0.2" 2024-01-16 LTS
Java(TM) SE Runtime Environment (build 21.0.2+13-LTS-58)
Java HotSpot(TM) 64-Bit Server VM (build 21.0.2+13-LTS-58, mixed mode, sharing)