What is the right position of literals in String Comparison?

Question

I have

if (localName.equals("TaxName")) {

but PMD says

Position literals first in String comparisons

Answer 1

"TaxName".equals(localName) is better as if localName is null you won't get a null pointer exception.

Answer 2

PMD should also be telling you why it generates this warning. From the rules documentation on the PMD website:

Position literals first in String comparisons - that way if the String is null you won't get a NullPointerException, it'll just return false.

Answer 3

I prefer to position literals first, i.e. :

if ("TaxName".equals(localName)) { ...

This way you do a right comparison for the case of null, instead of getting NullPointerException.

Answer 4

Personally, that doesn't make sense to me. If the code catches a NullPointerException, then it's done work that you won't have to do later. If localName ends up being null, and that causes a problem later on, then it'll be harder to trace. Don't change code to make the compiler happy. If your code throws a NullPointerException, then it's saved you debugging time later.