It could have been impossible, but you never know if there is a way to escape language VM barriers. However, the author clearly ignored the DNS hostname limit stated in RFC1123 [1], which is hardcoded even in Java libraries.
> A host name in a URL has no real size limit, but libcurl’s URL parser refuses to accept names longer than 65535 bytes. DNS only accepts host names up 253 bytes. So, a legitimate name that is longer than 253 bytes is unusual. A real name that is longer than 1024 is virtually unheard of.
DNS is not the only mechanism for resolving host name to address, even if it's what's used 99.9% of the time today.
Host software MUST handle host names of up to 63 characters and
SHOULD handle host names of up to 255 characters.
The DNS defines domain name syntax very generally -- a
string of labels each containing up to 63 8-bit octets,
separated by dots, and with a maximum total of 255
octets.
It can just as well mean, that the compiler will attempt to execute a proof, that memory is never accessed out of bounds, without well defined ownership and within the lifetime of the underlying object. Which is what Rust does, for example.
Of course it can also mean, that the compiler will then additionally add internal failure checks and safeguards at critical places (Rust does not do this, but it would be nice to have in systems where one might worry about in-register bit-flips (high radiation environments, like X-ray scanners), i.e. stuff not caught by – say – e.g. ECC memory).