This is the output for "jdk/bin/java -XX:+Verbose --version " command on a z16 hardware:

CPU Version as detected internally: system-z, g9-z15, ldisp_fast, extimm, pcrel_load/store, cmpb, cond_load/store, interlocked_update, txm, vectorinstr, instrext2, venh1, instrext3, venh2, out-of-support_as_of_tbd, aes128, aes192, aes256, sha1, sha256, sha512, ghash

So the issue is that z16 should be recognized as g10-z16 but instead I got g9-z15.