OpenJDK serves as the upstream for many Java distributions (maybe all?) and it has no notion of LTS. LTS is just something to which vendors commit as outlined at https://openjdk.java.net/projects/jdk/17/ : “JDK 17 will be a long-term support (LTS) release from most vendors.”.

In other words, OpenJDK does not follow any LTS/non-LTS release cycle. Hence there is nothing special about Java 17 vs 16 when it comes to stability.

Even preview features are production ready (I used them in production) . Just the api might change or it could be removed, but quality wise it is as good as it can be.