The current version is implemented by using GraalVM and an existing JavaScript implementation. This causes troubles with other JVMs, such as the Eclipse OpenJ9 VM: eclipse-openj9/openj9#11555.

This issue tries to make the desire of a pure Java implementation explicit. Maybe, it helps to shape a project tackling this wish.

Side note: There are transpilers from Java to JavaScript available (e.g., jsweet or j2cl), however, there is no JavaScript to Java transpiler (cf. https://awesomeopensource.com/projects/transpiler).

Also refs JabRef/jabref#5622 (comment).