Hi @ze2
Yes, it is possible. In fact, I think you must record with Katalon Studio and THEN change/instantiate the WebDriver in the script.
About your challenge, what test library are you using and what capabilities does it provide that Katalon lacks ? Since Katalon Studio uses Groovy - a Java-based scripting language, you can pretty much develop in Java entirely if you want.
If that’s not what you mean by Java Dev Env, then I suppose you are asking for APIs from Katalon to be called in your Java application ? If that’s the case then we are developing Katalon Platform that allows users to write plug-ins that can extend Katalon’s capabilities.
It’s not exactly an API ( in the sense of a JAR file that you can import in your test in other IDEs), but in the future you can develop plug-ins that export Katalon’s test cases into other formats. The Platform is still currently in BETA and under development, but we have published it so you may want to take a look in case existing infrastructures can help you leverage Katalon for your automation testing.
Have a nice day !