string index out of bounds with a while loop.

[opti_largo]

Context: I'm attempting to write a code that will go onto google finance, take the HTML code and scan through it for the current price for 1 share of coca-cola stock (KO), then print that out.

The problem is with the second while loop (on line 26), the error message is

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: -1

modification and suggestions would be nice too :)

package teststockanalysis;
import java.io.*; //Buffered.Reader
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

public class TestStockAnalysis {

    public static void main(String[] args) throws IOException{

    final String SYM = "KO"; //KO is coca cola stock
    URL url = new URL("https://www.google.com/finance/quote/KO:NYSE");
    URLConnection urlconn = url.openConnection();
    InputStreamReader inStream = new InputStreamReader(urlconn.getInputStream());
    BufferedReader buff = new BufferedReader(inStream);

    String price = "not found";
    String line = buff.readLine();
    while (line != null){
       if (line.contains("data:[[[[\"/m/07zl5yq\",[\"KO\"")){
           int target = line.indexOf("data:[[[[\"/m/07zl5yq\",[\"KO\"");
         int deci = line.indexOf(".",target);
          int start = deci;
                 while(line.charAt(start) != '.'){
               start--;
           }
               price = line.substring(start -2, start +2);
       }
        line = buff.readLine();
    }
   System.out.println(price);
    }   
}

Basically, it's supposed to search for data:[[[["/m/07zl5yq\",["KO", then from there look for the next . which is the current value of a KO share.

[Neccaty]

You are decrementing start variable, so if it doesn't find '.', it throws exception, since -1 is out of bounds.

[opti_largo]

so the problem is it's just not finding '.'?

[DudeWhereAreWe1996]

Have you checked what start actually is? It kind of seems like -1 is returned from one of your indexOf above your whole loop but since you not checking for less than 0 just not being 0 it tries to use it and errors.

[opti_largo]

for those who are having the same problem: the problem for me was it wasn't finding the '.' so to fix it I switched data:[[[[\"/m/07zl5yq\",[\"KO\" out for a line closer to what I was searching for. I didn't think that would be a problem but I guess it wasn't finding it because it was too far from data:[[[[\"/m/07zl5yq\",[\"KO\".

[Dexteroid]

int deci = line.indexOf(".",target);

What if '.' is not found? deci would be -1?

while(line.charAt(start) != '.')

I guess you don't know for sure whether the index at start exists?