[kreijstal]

java did run in the browser once.... it was embedded directly on the browser there was also nsapi

you could also run java with js if you are brave enough https://kreijstal.github.io/java-tools/

[TeaVMFan]

Java runs in the browser currently, after a transpilation step (same as .ts):

https://teavm.org/

[gf000]

Also CheerpJ (with support for Swing UIs even), Closure compiler, and now GraalVM also has an experimental WasmGC target.