comparing strings using !=

Question

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How do I compare strings in Java?

I am trying to compare a striong using || operator..

if(publisher != "Niho books" || publisher != "Diamond Comics" )

what is wrong in this ? Strings can't be compared like this ??

sabisabi · Answer 1 · 2012-06-11T08:31:45.073

This should work:

if (!"Niho books".equals(publisher) || !"Diamond Comics".equals(publisher))

http://www.leepoint.net/notes-java/data/strings/12stringcomparison.html

Dont use ==, != for String compare
equals() can go after publisher or after your string (publisher.equals() or "string".equals()) , I think the second one is maybe better because if your publisher is a null you wont get nullpointer exception. But do however you like/is right for you

score 4 · Answer 2 · answered Jun 11 '12 at 08:27

4

In this way you are not comparing contents... you are comparing references.

If you want to compare contents then use

publisher.equals("Niho books")

or 

publisher.equalsIgnoreCase("Niho books")

answered Jun 11 '12 at 08:27

Pramod Kumar

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score 3 · Accepted Answer · answered Jun 11 '12 at 08:27

3

Don't use != or == to compare strings in Java. Use .equals() instead. The != and == operators compare references, not the content of objects.

if (!publisher.equals("Niho books") || !publisher.equals("Diamond Comics"))

answered Jun 11 '12 at 08:27

Jesper

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OP's asking why he should'nt use `!=` to compare Strings. – Luiggi Mendoza Jun 11 '12 at 08:28
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@LuiggiMendoza So, that's what I explained, didn't I...? – Jesper Jun 11 '12 at 08:28

score 2 · Answer 4 · answered Jun 11 '12 at 08:28

2

In strings, equals() tests the equality of value where as != and == tests equality of the references.

answered Jun 11 '12 at 08:28

Anuj Balan

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score 1 · Answer 5 · edited Jun 11 '12 at 08:27

1

no, strings should be compared like this:

publisher.equals("Niho books")

edited Jun 11 '12 at 08:27

Sirko

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answered Jun 11 '12 at 08:26

mooonli

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score 1 · Answer 6 · answered Jun 11 '12 at 08:26

1

http://www.devdaily.com/java/edu/qanda/pjqa00001.shtml read this

answered Jun 11 '12 at 08:26

dontcare

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comparing strings using !=

6 Answers6