Cannot find symbol

[John Paterson]

Hi Folks,

Some issue I am having with some code I wrote. The code as follow:

public class Finder extends Thread{
    
    public Finder(int search, int begin, int end){
        
        int srch = search;
        int bgn = begin;
        int nd = end;
        
        
    }
    
    public void run(){
        
        
        for(int i = srch; i < nd; i++ )
        {
            
        }

I am getting a 'Cannot find symbol' error that says srch can't be found. Why am I getting this error? srch is declared in the constructor already so why this error? Hope someone can advise. Thanks.

regards
John

[Kemal Sokolovic]

Please post SSCCE.

It is not enough to declare variables in constructor in order to use them throughout your class. You need to declare them as class fields (outside the constructor), otherwise they just act as local variables for the constructor (or any other block of code).

Edit: Playing around with threads without getting along with scope of variables is a tricky business by my oppinion.

[John Paterson]

Hi Kemal Sokolovic ,

Noted. Thanks.

regards
John

[Rajdeep Biswas]

Hi John,

In java you got different scopes, class level, method level, etc...

So had you declared these variables in class level, you would not have got the error. But here, you have declared them in constructor, so compiler can see them inside that particular constructor only, and not in other scopes....so you are getting "can not find symbol" error....

    public class Finder extends Thread{  
        int srch, bgn, nd;

        public Finder(int search, int begin, int end){  
              
            srch = search;  
            bgn = begin;  
            nd = end;              
        }
        public void run(){      
            for(int i = srch; i < nd; i++ )  
            {  
                  
            }  

Hope that helps.
Regards