Following the instructions listed at https://docs.oracle.com/en/java/javase/17/docs/specs/man/javac.html#command-line-argument-files - Examples of Using javac @filename - Two Argument Files yields (on Windows):

    javac @options @classes
    ❌ error: not a directory: classes

Workaround and possible fix: Rename the second Argument File from "classes" to "sources" in order to prevent a clash of names.

    rename classes sources
    javac @options @sources
    ✅

Or change the name of the output directory from `-d classes` to `-d out`.