Should I use string isEmpty or equals string

Question

I m usually testing this alongside a string    null  so I m not really concerned about a null-safe test  Which should I use  String s      whatever         if  s    null     quot  quot  equals s            handle some edge case here    or if  s    null    s isEmpty             handle some edge case here    On that note - does isEmpty   even do anything other than return this equals  quot  quot    or return this length      0

User · Answer

It doesn t really matter     equals str  is more clear in my opinion   isEmpty   returns count    0

User · Answer

The main benefit of    equals s  is you don t need the null check  equals will check its argument and return false if it s null   which you seem to not care about  If you re not worried about s being null  or are otherwise checking for it    I would definitely use s isEmpty    it shows exactly what you re checking  you care whether or not s is empty  not whether it equals the empty string

User · Answer

I wrote a Tester class which can test the performance  public class Tester       public static void main String   args                String text    quot  quot            int loopCount   10000000          long startTime  endTime  duration1  duration2           startTime   System nanoTime            for  int i   0  i  lt  loopCount  i                  text equals  quot  quot                      endTime   System nanoTime            duration1   endTime - startTime          System out println  quot  equals   quot   quot   duration  quot    quot    t quot    duration1            startTime   System nanoTime            for  int i   0  i  lt  loopCount  i                  text isEmpty                      endTime   System nanoTime            duration2   endTime - startTime          System out println  quot  isEmpty   duration  quot   quot    t t quot    duration2            System out println  quot isEmpty   to equals   quot   quot   ratio   quot      float duration2    float duration1             I found that using  isEmpty   took around half the time of  equals  quot  quot

User · Answer

One thing you might want to consider besides the other issues mentioned is that isEmpty   was introduced in 1 6  so if you use it you won t be able to run the code on Java 1 5 or below

User · Answer

You can use apache commons StringUtils isEmpty   or isNotEmpty

User · Answer

String equals     is actually a bit slower than just an isEmpty   call   Strings store a count variable initialized in the constructor  since Strings are immutable   isEmpty   compares the count variable to 0  while equals will check the type  string length  and then iterate over the string for comparison if the sizes match   So to answer your question  isEmpty   will actually do a lot less  and that s a good thing

[java] Should I use string.isEmpty() or "".equals(string)?

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