The latest version of SnapCode supports Java 11 in the browser (the download version supports Java 21). SnapCode offers real native Java Client graphics in the browser and desktop.

SnapCode is free and uses the CheerpJ browser JVM to run real Java in the browser. CheerpJ is moving quickly this year to support the latest versions of Java. Java 11 this month, Java 17 this summer, and hopefully release parity soon after.

SnapCode: https://reportmill.com/SnapCode/

CheerpJ: https://labs.leaningtech.com/blog/cheerpj-4.0