In 2016 I worked on a project with a client who still mandated that all code was written to the Java 1.1 language specification - no generics, no enums, no annotations, etc., not to even mention all the stuff that's come
since 1.5 (or Java 5, or whatever you want to call it). They had Reasons(tm), which after filtering through the nonsense mostly boiled down to the CTO being curmudgeonly and unwilling to approve replacing a hand-written code transformer that he had personally written back in the stone ages and that he 1) considered core to their product, and 2) considered too risky to replace, because obviously there were no tests covering any of the core systems...sigh. At least they ran it all on a modern JVM.
But no, it would not surprise me to find a decent handful of large companies still writing Java 5 code; it would surprise me a bit more to find many still using that JVM, since you can't even get paid support through Oracle anymore, but I'm sure someone out there is doing it. Never underestimate the "don't touch it, you might break it" sentiment at non-tech companies, even big ones with lots of revenue, they routinely understaff their tech departments and the people who built key systems may have retired 20 years ago at this point so it's really risky to do any sort of big system migration. That's why so many lines of COBOL are still running.
