Optionals Bad And Good Practice

Enjoy! :-)
Thank you for commenting and asking questions.
Discord server - Where we discuss programming languages and tech - Please use the right channel to your input / question :)
/ discord
My web site:
www.codeinvestigator.com
One.com - Easy web sites
one.me/daauttew
The code is located here:
github.com/ekim197711
Follow me on twitter:
/ mikemoelnielsen
Chat on Discord:
/ discord
Support me on Patreon:
/ mikemoellernielsen
Background nature video:
Video by Engin Akyurt from Pexels
www.pexels.com/video/beauty-o...

[@lost.empathy]

Thank you. I was wondering why in some parts of our legacy projects we have Optional of List in JPA Repositories. It was so because sometimes people got null if they wrote @Query with unused method parameter. But as I read in docs repository methods guarantee to return collections or whatever was set as return wrapper type. What do you think, should I do null checks when I get data from repository methods or NPE itself will point to bad quality code?

[@MikesTechCorner]

This is a very good example. The Reposities can return Optional but should never return Optional. And making mistakes with query parameters is a common mistake. :)

[@ilyastuit]

Nice video!
I’m wondering why is it bad practice to “use Optional with Lists/Collections”.
Let’s consider the case when I have reference to List, but I don’t know whether it is null or empty, and I want to perform some actions declaratively / in a functional manner.
With Optional:
List otherElements = Optional.ofNullable(potentiallyNullOrEmptyList)
.filter(elements -> !elements.isEmpty())
.map(elements -> repository.findAllByXXAndWhereElementIn(..., elements))
.orElse(Collections.emptyList());
Without Optional:
List otherElements;
if (potentiallyNullOrEmptyList == null || potentiallyNullOrEmptyList.isEmpty()) {
otherElements = Collections.emptyList();
} else {
otherElements = repository.findAllByXXAndWhereElementIn(..., potentiallyNullOrEmptyList));
}

[@MikesTechCorner]

If you get a List declard object from somewhere and it is null then you should have had an empty list instead. That is the thought behind not wrapping Lists in optionals. Lists are already wrappers.

[@r2-p2]

@@MikesTechCorner Except if the empty list has a different meaning than no list.

[@MikesTechCorner]

@@r2-p2then you should change the meaning so there is always a list. Use real readable logic to handle the situation where you had a "null" list.