Should I delete an answer of mine that was accepted but might not be helpful for further visitors?

Question

I read a lot about deleting the own posts, for example:

Under which circumstances should I delete my own question or answer
When should I delete my posts?
Should I delete my answers?

But I think I have a different scenario from the above questions.

In this question, I knew the answer right after the OP pointed where the line with the error was, via a comment, then I started writing my answer, when I published I saw that another user posted the answer in a comment to the question. Right after, the question received a downvote, probably because it is too localized or even because the OP didn't put any effort on it.

The OP accepted my answer as correct, okay so far. But I start wondering: maybe, the question is not useful for further visitors, and as the question has a downvote it can be eliminated from the SO forever after 30 days as per this topic says so.

So my doubt is, to keep my answer makes me a rep-whore? To delete it is of any benefit to SO? Maybe, should I delete it just after 30 days to make sure nobody else is going to answer it and make the questions to stay there forever? Should I flag the question to be deleted?

Considering that I want the best to the community, what should I do afterall?

Answer 1

In this case, you could make that post useful to others. NPE is a common problem that most could probably figure out on their own with a quick search of reading the error log.

However, since they usually seem to not search for it, you could explain how you were able to come up with what the problem was. Edit the answer and explain how you got the line number, class, variable information, etc... then other who search for a NullPointerException may see this and learn some debugging skills.

For example, this is an answer of mine where I did just that.

Doing this will take a very localized question and make it helpful to many others. Obviously, this question could have been improved before answering (as Servy mentioned) or probably closed as a duplicate of many other NPEs but since it is already answered and accepted that would be my advice.