make sure that a ServiceLoader is retrieved before iterating

[RangerRick]

fixes #10168

[gregw]

@RangerRick thanks for the PR. As 9 is end of community support, we can't say if this will get merged or if it does if/when there will be another release.

However, for us to merge it, we would need the ECA to be signed. If you don't sign it, then we need to find a developer who has not seen your contribution to fix this issue (if we decided to do it).

[RangerRick]

@gregw yeah I figured it was a long shot, but it was worth submitting. Because of the interdependencies between karaf and pax and ourselves, moving to 10 is an ongoing project but in the meantime I'm trying to solve the race. :)

As for the ECA, I've signed it now, not sure how to make it re-check.

update aha! the "details" on the ECA failure took me to a page to re-validate. :)