The reason you're being downvoted is you keep dismissing this as a "toy" project, and pointing out that it would be hard to make a real project.
But, as the previous commenter attempted to point out to you this project is a *self-described* toy project.
On the very page that is linked, the author of the JVM specifically says:
"I want to stress that this is a toy JVM, built for learning purposes and not a serious implementation."
Thus, absolutely no one disagrees that its a toy JVM. They just want you to stop being dismissive of someone's toy project by repeatedly pointing out its a toy project and not a "not a thing"
But, as the previous commenter attempted to point out to you this project is a *self-described* toy project.
On the very page that is linked, the author of the JVM specifically says:
"I want to stress that this is a toy JVM, built for learning purposes and not a serious implementation."
Thus, absolutely no one disagrees that its a toy JVM. They just want you to stop being dismissive of someone's toy project by repeatedly pointing out its a toy project and not a "not a thing"