Java isEmpty or "".equals for performance

Question

I'm writing a lot of components in Adobe CQ so have to deal a lot with user set properties. And i'm getting a little tired of all the null checks before I can do an isEmpty check.

I'd like to do something like.

"".equals(string);

This would be a lot more readable, but how would it compare performance wise. And yes i would expect to create the "" as a constant if there where multiple checks.

Thanks D

even if it does some small preformence improvment, will it even be noticable for the end user? — David Haim, Jul 21 '15 at 08:26

Pol · Answer 1 · 2015-07-21T08:26:59.927

1

It is preferred to use the isEmpty() method(Simpler and faster source code ). Another efficient way to check empty string in java is to use:

string.length() == 0;

edited Jul 21 '15 at 08:26

answered Jul 21 '15 at 08:15

Pol

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Please add to your answer why the first method is preferred. – JackWhiteIII Jul 21 '15 at 08:19

score 1 · Answer 2 · answered Jul 21 '15 at 08:22

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Personally I use Apache's StringUtils, eg:

if (StringUtils.isEmpty(someString)) {
    ...

or

if (StringUtils.isNotEmpty(someString)) {
    ...

Also I really wouldn't worry about the performance of this unless you have benchmarked an identified it as an issue

answered Jul 21 '15 at 08:22

beresfordt

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Yeah, adding a 3rd party library to call a single method, is really a big win. And `StringUtils.isEmpty(someString)` looks so much better than `someString.isEmpty()`… – Holger Jul 21 '15 at 08:49
I have never worked on a project where there has not been extensive use of apache.commons.lang3; there is a lot of useful stuff in there – beresfordt Jul 21 '15 at 09:06
of course. If you add that library as soon as you find a method which does the same as an existing JRE method, you won’t have any project without it. And not to forget, the useful constants: `StringUtils.EMPTY`; no more need to type `""` all the time… – Holger Jul 21 '15 at 09:15
`StringUtils.isEmpty` is actually a `null` or empty check. So on the surface `someString.isEmpty()` works until there is any possibility that `someString == null` – Cameron Hotchkies Dec 10 '15 at 23:03

score 0 · Answer 3 · answered Jul 21 '15 at 08:14

0

You should not care about performance here. Both version have similar speed. Even if they compile differently, JITted code will unlikely to differ more than several CPU cycles (especially given the fact that String.equals is JVM intrinsic). Not the thing you should worry about when programming on Java.

answered Jul 21 '15 at 08:14

Tagir Valeev

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I think the String.equals is the easiest to read which is the biggest win for me. And if the performance is around the same i'll argue my case if it get brought up in the code review. Thanks for the input. – DamianM Jul 21 '15 at 14:02

Java isEmpty or "".equals for performance

3 Answers3