Error Prone VS jqwik

error-prone is good for some extra static analysis.

A special kind of validation is enforcing that record fields are not null. (Un)fortunately, records do not have any special behavior regarding nullability. You can use tools like NullAway or Error Prone to prevent null in your code in general, or you can add checks to your records:

I am all in favour to more third side libraries adding functionalities, like Lombok, Manifold and error prone. As well as smaller projects like this shameless plug and what appears in this list

If only Google didn't suck when it came to Java9+ support... https://github.com/google/error-prone/issues/2649

I haven't used it. I use Google's ErrorProne + Lombok to prevent NPEs in java.

Take a look at NullAway, a plugin for Error Prone.

For some of this stuff, there are compiler extensions that allow extra type checking to be added e.g. Google Error-Prone: https://github.com/google/error-prone with stuff like: https://errorprone.info/bugpattern/ReturnMissingNullable.

Doesn't help you with third party libraries, but across an org applying that rule (and others!) typically ensures some consistency.

How to build a static analysis plugin. Google has a framework for Java with a good tutorial.

See https://jqwik.net

Once we knew which property to use it was very straightforward to add a property-based test for it. We used the jqwik library. We like it because it has very good documentation and it is integrated with Junit.

Jqwik - I love property based testing and the way it can make you think differently about some of your code.

Different to mutation testing, but on a semi-relatednpath, I've found property-based testing (e.g. https://jqwik.net/) to be valuable - thinking about the “shape“ of the expected output and getting a bunch of pseudorandom tests is pretty handy, especially for utility functions.