Is it bootstrappable? I mean really bootstrappable, not "the bootstrap script will download a binary from some server". This is where both Maven and Gradle fail

Is it bootstrappable? I mean really bootstrappable, not "the bootstrap script will download a binary from some server". This is where both Maven and Gradle fail (at least the last time I checked). Kotlin and Scala also have the problem that their compilers themselves are not bootstrappable either.