Hi, we have started using Adaptavist as our test management tool. We would like to integrate this plugin with our Automation suite which is written in Java. Is the jira rest java client compatible with this API?
JRJC is a library written for Jira.
ScriptRunner adds other functions that the JRJC cannot possibly know about. So it won't have anything to do with those functions. But it is "compatible", because it talks to Jira and SR doesn't change what Jira exposes to it.
It's a bit more complex than I think you have described. I could just say "no" to answer your last question, but I think it is worth explaining what you are looking at.
We all know we have a Jira system, providing issues, projects, users, workflows and so-on. This includes a GUI front end for us humans.
This system has a REST interface it exposes to the outside world, so that other computers can talk to it without using the GUI which just gets in their way. Obviously, to use it, you need to code for it.
Atlassian provide a java based library called JRJC that tries to help you with it. As a random example, if you ask the Jira REST API for an issue manually, you'll get a big block of text encoded with information about all the fields and so-on, but it is plain text. Your code would have to work out what it was looking for in there, extract it and work with it, with no real understanding that the block of text was a "Jira issue". JRJC gives you some structure to the interface, so you don't have to code for those concepts yourself.
ScriptRunner is a plugin/add-on/app for Jira that adds extension points where you can write code inside Jira. You can write calculated custom fields, workflow functions, JQL functions, automation scripts and so-on. All of those are internal to Jira though and if they're exposed over REST in any way, it's via the core functions. A ScriptRunner field looks like any other field when you ask for it via REST.
The exception here is that SR also allows you to write your own REST endpoints. Because they are not part of Jira themselves, and you could do absolutely anything with them, JRJC can't handle them - it's not written by Adaptavist, but more importantly, your REST endpoints could be doing anything.
So, no, there's no libraries for SR REST endpoints, because there is simply no way for us to know what you are going to do with them.
Technically, it's "compatible" in the sense that it will not break.
But it can't possibly do anything with ScriptRunner either. It's a bit like saying a screwdriver is "incompatible" with a freezer if you put it in there. You can freeze a screwdriver if you want, but it's not going to do much to help you cook your dinner.