cfml

<https://dev.lucee.org/t/switching-java-regex-engines-on-the-fly/11491>

It's definitely not intuitive to me that the use of `&lt;cfapplication /&gt;` is per-request, at least in the terms of updating the settings.

I knew the settings were read on each request, but I just assumed trying to change something about the application settings would not be thread safe.

That's good to know.

<@U070SQMD1> Any idea how it affects code running in a thread?

good question, a thread runs as a child of the parent pageContext()

So switching the application settings like this for the regex engine, could break any threads that were spawned in the request that relied on regexes.

but when new threads child page context are created, they inherit what ever was running at the time

we are probably going to also add a `engine="java"` to the regex BIFs too

ok, so a thread clones the page context and doesn't use a reference. That's good to know too.

yep, which is why there's some overhead with threads