Because this is a community-driven port of a very recent Minecraft version, it is not without flaws:

: Since 1.13, Minecraft eliminated numeric data values for blocks (e.g., ) in favor of unique textual identifiers ( white_wool

: Many repositories are still in active development. As noted by developers at Nate2018's Eaglercraft-1.21.1-TeaVM , the login screen may be missing in some builds, and certain game logic handled by TeaVM can occasionally behave unpredictably.

Was this the kind of you were looking for, or were you looking for a download link to a specific beta version of the project?