I built another project called p5forge that transpiles Processing-style code to p5.js in the browser. You can use the command-line tool and the online IDE.
It is not a full Java compiler, it is a practical converter for common sketch patterns and most Java-like syntax (AST). The Project also supports PDEZ-Files! (see example linked in README) Thanks to vibe coding, the project is very powerful. I would be pleased if someone would contribute to its further development.
Repo: GitHub - OTH-AW-Meiller/p5forge: Convert Processing-style sketches to p5.js fast, with a built-in browser preview · GitHub
Demo: p5forge — run Processing (Java) sketches in the browser