Why don't strings compare as equal?

Question

Possible Duplicate:
String is not equal to string?

I'm new to java and I can't figure out what's wrong with this code block. I know the array isn't null I'm testing it elsewhere. Maybe there is a syntax problem I'm used to program in c#.

     Scanner input = new Scanner(System.in);
     System.out.println("Enter ID :");
     String employeeId = input.nextLine();
     int index =  -1;
     for(int i = 0 ; i < employeeCounter ; i++)
     {
         if(employeeId == employeeNumber[i])
         {
           index = i;
         }
     }

     if(index == -1)
     {
         System.out.println("Invalid");
         return;
     }

I always get to the 'Invalid' part. Any idea why ? Thanks in advance

employeeNumber[0] is "12345" employeeId is "12345" but I can,t get into the first if statement although employeeId IS equal to employeeNumber[0].

What's employeeCounter? Please paste the full code. – sgowd Apr 25 '12 at 05:33 — sgowd, Apr 25 '12 at 05:33
use .equals() for String comparisons. – tronbabylove Apr 25 '12 at 05:34 — tronbabylove, Apr 25 '12 at 05:34

score 12 · Accepted Answer · edited Aug 19 '16 at 21:39

12

Don't compare strings with ==.

Use

if (string1.equals("other")) {
    // they match
}

edited Aug 19 '16 at 21:39

Maytham Fahmi

31,138
14
118
137

answered Apr 25 '12 at 05:33

John3136

28,809
4
51
69

2

`"other".equals(string1)` is the preferred way -- Null save. – Rudolf Mühlbauer Oct 13 '12 at 23:30

score 6 · Answer 2 · answered Apr 25 '12 at 05:33

6

Compare strings like that

if(employeeId.equals(employeeNumber[i]) {

}

answered Apr 25 '12 at 05:33

juergen d

201,996
37
293
362

score 4 · Answer 3 · answered Apr 25 '12 at 05:37

As others have pointed - full code will be helpful, but my guess would be this line of the code:

if(employeeId == employeeNumber[i])

You don't compare 2 strings by using ==. Use equals() or equalsIgnoreCase() instead. == only checks for object equality i.e. are employeeId and employeeNumber referencing to the same object in memory. So, for objects always use the equals() method..for Strings you can also use equalsIgnoreCase() for a case insensitive match. == should be used on primitive types like int, long etc.

score 3 · Answer 4 · answered Apr 25 '12 at 05:33

3

When you use == with two string, it compares pointer addresses You should use firststring.equals(secondstring) in order to compare two strings

answered Apr 25 '12 at 05:33

omartin

135
1
16

score 2 · Answer 5 · answered Apr 25 '12 at 05:34

2

Use equals() method to compare Strings

if(employeeId.equals(employeeNumber[i])){}

answered Apr 25 '12 at 05:34

Shashank Kadne

7,993
6
41
54

score 2 · Answer 6 · answered Apr 25 '12 at 05:51

2

When you compare strings, use String1.equals(String2); This should give you the result

answered Apr 25 '12 at 05:51

beachwood23

431
2
5
14

score 0 · Answer 7 · answered Apr 25 '12 at 05:41

0

"==" checks whether the reference for two objects are same. But equals() method checks whether the content is same or different.

answered Apr 25 '12 at 05:41

Dheeraj Joshi

3,057
8
38
55

Why don't strings compare as equal?

7 Answers7