See the Native SDK for Java - here are the specific Docs for manipulating Globals as you asked (but the API provides other access types).

There are some related Open Exchange apps - native-api-command-line-java by @Robert Cemper and native-api-contest-template by @Bob Kuszewski you can also use as samples.

I was able to do it with Okta's auth0.

See some info in this post.

For IRIS, since 2025.3, there is a new option for FIFO handling (even with pool size > 1).

See related Docs - Maintaining First-In First-Out (FIFO) Processing and related video Multi-threading an HL7 Interface and scaling beyond FIFO constraints by @James MacKeith