HHH-12346: Replace StringHelper#join by Java's String#join

[kinow]

This pull request replaces a couple of StringHelper#join methods and its occurrences by Java 8's String#join.

As I mentioned in the JIRA ticket, this is a left-over after I submitted another pull request. I had noted this class methods, and noticed at least the join could be replaced.

Had to use streams in three places to convert from Integer to String.

Not a problem if it is decided not to touch this method for being in core module, or because it just works :-) Otherwise, let me know if further testing, syntax, formatting, etc, is necessary. Happy to update the ticket with new commits, squash, rebase, etc.

Cheers
Bruno

[kinow]

Travis CI failed in the check part. I did only clean test (more familiar with Maven, sorry). Updated code, re-run with check, and confirmed this part passed now. Let's see if Travis CI can build it fine now.

[sebersole]

I'd prefer to not use Streams for the conversion. We have run perf tests on using Streams for such operations and they perform significantly worse. I did not see such calls in my quick look over the changes - just based in your comment.

A better option might have been to simply have overloaded methods on StringHelper to take Strings versus Objects. Calls involving Strings could have delegated to String#join

[kinow]

Good point @sebersole . I've found situations where debugging problems was trickier because of streams, so I don't see why not try a different approach.

Reviewing the changes, also noted another part that could be simplified. Now instead of streams, or another method, simply calling #iterator() appears to work fine. WDYT?

Updated, ./gradlew clean test check passed after some 20 minutes locally, so hopefully Travis build will be OK as well.

[sebersole]

simply calling #iterator() appears to work fine. WDYT?

I'm not sure what this means. Can you point me to an example of what you mean?

[kinow]

Sorry for not being clear on the iterator use @sebersole

I meant that instead of maintaining a mehod for iterable, used in only a couple of places, we can simply maintain an iterator method, and call .iterator ou iterables, keySet, etc... like in here https://github.com/kinow/hibernate-orm/blob/918a50326ff8c7b893edf6aee74638c82c10d29b/hibernate-core/src/main/java/org/hibernate/query/internal/ParameterMetadataImpl.java#L68