I have been wondering recently about usage of empty string vs null.
I know what these values mean, but I wonder when I should use each? It is not about exact programming language or approach.
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1every programming language is different and has a different (similar sometimes) behaviourKonrad– Konrad2018-09-11 07:24:04 +00:00Commented Sep 11, 2018 at 7:24
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but shortly: string initialized with null means that there's no string at all, empty string means there's a string but it's empty, if someone else is using your API then you might decide to not accept null or empty so you have to check for both.Konrad– Konrad2018-09-11 07:25:52 +00:00Commented Sep 11, 2018 at 7:25
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2 Answers
As a general guideline, I avoid using null no matter what.
null is not an object, it can't do anything and you can't expect anything from it. It will evenatually leak as a rather obscure NullPointerException. You can't access any field or any method in null and trying to do so, will lead you to the aforementioned excpetion.
You can avoid using it with:
Null Objectpattern- Raising
Exceptionwith a more useful than message than an emptyNullPointerException - Designing your classes to have its fields
private finaltherefore avoiding nulls by design
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Moste of the time you want to prevent both. The difference is that a null value is returned most of the time when you try to use a variable which doesn't exist or has not been instantiated by you or the programm. The empty string is most of the time a human approach of emptying a variable which already exists.
