Technically? Yes, Correto is it's own separate distribution that Amazon manages porting upstream changes into. Same as how Azul's Zulu is a "competitor" as well.

Practically speaking, it shouldn't matter as they all pass the Java TCK.

1. AdoptOpenJDK does not run the TCK.

2. Corretto and Zulu each have their own patch set. Corretto backports a couple of G1 fixes and Zulu backports Flight Recorder and TLS 1.3.

Although no TCK we do run > 100,000 open tests, including many popular open-source libraries, frameworks and languages. We're very comfortable standing behind the quality of these binaries :-).

1. Ooh that's good to be aware of...