Is making an empty string constant worth it?

Question

I have a co-worker that swears by

//in a singleton "Constants" class public static final String EMPTY_STRING = ""; 

in a constants class available throughout the project. That way, we can write something like

if (Constants.EMPTY_STRING.equals(otherString)) {     ... } 

instead of

if ("".equals(otherString)) {     ... } 

I say it's

1. not worth it--it doesn't save any space in the heap/stack/string pool,
2. ugly
3. abuse of a constants class.

Who is the idiot here?

Answer 1

String literals are interned by default, so no matter how many times you refer to "" in code, there will only be one empty String object. I don't see any benefit in declaring EMPTY_STRING. Otherwise, you might as well declare ONE, TWO, THREE, FOUR, etc. for integer literals.

Of course, if you want to change the value of EMPTY_STRING later, it's handy to have it in one place ;)

Answer 2

Why on earth would you want a global variable in Java? James Gosling really tried to get rid of them; don't bring them back, please.

Either

0 == possiblyEmptyString.length() 

or

possiblyEmptyString.isEmpty() // Java 6 only 

are just as clear.