Trouble comparing string's in java

Question

Why does this return true?

String b =  "(5, 5)";
String a =  "(7, 8)" ;
if(a.equals(b));
{

    System.out.printf("Somehow \"%s\" and \"%s\" are the same" ,a,b);
}

Output:

Somehow "(7, 8)" and "(5, 5)" are the same

[Why do java if statement fail when it ends in semicolon?](http://stackoverflow.com/questions/12772221/why-do-java-if-statement-fail-when-it-ends-in-semicolon) — Bernhard Barker, Feb 10 '14 at 07:34

score 5 · Answer 1 · answered Feb 10 '14 at 07:28

5

Your code is equivalent to:

if(a.equals(b)) { }
{
   System.out.printf("Somehow \"%s\" and \"%s\" are the same" ,a,b);
}

So the print statement in a block that'll be always executed regardless of the condition, since the body of the if doesn't include that statement.

See the JLS - 14.6. The Empty Statement:

An empty statement does nothing.

EmptyStatement:
; 
Execution of an empty statement always completes normally

answered Feb 10 '14 at 07:28

Maroun

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Ahh.. language specification. – Suresh Atta Feb 10 '14 at 07:31
1

I was about to post this link!! Edit: @sᴜʀᴇsʜᴀᴛᴛᴀ Read this http://stackoverflow.com/a/14112532/1673391 – Grijesh Chauhan Feb 10 '14 at 07:32
1

Fast and furious...... – Maroun Feb 10 '14 at 07:33
@GrijeshChauhan That's an useful link. – Suresh Atta Feb 10 '14 at 07:38
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He went to future in time and stole my link. – Maroun Feb 10 '14 at 07:39

score 4 · Answer 2 · edited May 23 '17 at 12:28

4

You have ; after your if statement.

use:

if(a.equals(b)) {
    System.out.printf("Somehow \"%s\" and \"%s\" are the same" ,a,b);
}

Take a look at this answer.

edited May 23 '17 at 12:28

Community

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answered Feb 10 '14 at 07:28

BobTheBuilder

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It might be helpful to also explain what happens when you put the semi-colon there. – Bernhard Barker Feb 10 '14 at 07:30

Suresh Atta · Answer 3 · 2014-02-10T07:39:50.353

1

if(a.equals(b));<-----

You have an extre ; there and statements ends there.

That's like writing

if(a.equals(b));

and a block here

{

    System.out.printf("Somehow \"%s\" and \"%s\" are the same" ,a,b);
}

So get rid of that extra ;

edited Feb 10 '14 at 07:39

answered Feb 10 '14 at 07:28

Suresh Atta

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*a static block here* - It is not a static block, AFAIK. – Rahul Feb 10 '14 at 07:35
@Ɍ.Ɉ So what you think of it ?? Can you please correct me ? – Suresh Atta Feb 10 '14 at 07:36
It is an [anonymous block](http://stackoverflow.com/q/1563030/2024761). This is a static block - `static { ... }`. – Rahul Feb 10 '14 at 07:38
1

@Ɍ.Ɉ I usually refer them static's :). There is a good reason to change it. Thanks. – Suresh Atta Feb 10 '14 at 07:39

score 0 · Answer 4 · answered Feb 10 '14 at 07:29

0

Your if condition satisfied, but nothing will execute since ; in following.

if(a.equals(b)); // ;  this is equal to if(a.equals(b)){}

Correct this as follows

if(a.equals(b)){
 System.out.printf("Somehow \"%s\" and \"%s\" are the same" ,a,b);
}

answered Feb 10 '14 at 07:29

Ruchira Gayan Ranaweera

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Weibo Li · Answer 5 · 2014-02-10T07:32:06.423

0

Because you typed a ; after the if statement. Then it will be evaluated as if(a.equals(b)){};, which means do nothing.

String b =  "(5, 5)";
String a =  "(7, 8)" ;
if(a.equals(b)); <-- remove this ';'
{
    System.out.printf("Somehow \"%s\" and \"%s\" are the same" ,a,b);
}

edited Feb 10 '14 at 07:32

answered Feb 10 '14 at 07:31

Weibo Li

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Trouble comparing string's in java

5 Answers5