I have frequently encountered the term in the context of unit testing and dependency injection.

Other references (and all predate chatgpt):

>Seams are places in your code where you can plug in different functionality

>Art of Unit Testing, 2nd edition page 54

(https://blog.sasworkshops.com/unit-testing-and-seams/)

>With the help of a technique called creating a seam, or subclass and override we can make almost every piece of code testable.

https://www.hodler.co/2015/12/07/testing-java-legacy-code-wi...

> seam; a point in the code where I can write tests or make a change to enable testing

https://danlimerick.wordpress.com/2012/06/11/breaking-hidden...

Maybe it all ultimately traces back to the book mentioned before, but I don't believe it's an obscure term in the circles of java-y enterprise code/DI. In fact the only reason I know the term is because that's how dependency injection was first defined to me (every place you inject introduces a "seam" between the class being injected and the class you're injecting into, which allows for easy testing). I can't remember where exactly I encountered that definition though.