String index out of range: -1

Question

I am making a program which takes screenshots and uploads them to imageshack.us, I have got the following code.
import java.awt.image.BufferedImage;
import java.awt.*;
import java.io.*;
import java.net.*;
import javax.imageio.ImageIO;
public class Screenshot extends Thread {
     public static void main(String[] args)
          new Screenshot().start();
     public void run()
          try {
               Robot robot = new Robot();
               BufferedImage screenShot = robot.createScreenCapture(new Rectangle(
                         Toolkit.getDefaultToolkit().getScreenSize()));
               ImageIO.write(screenShot, "PNG", new File("screenshot.png"));
               String image = uploadToIs("screenshot.png");
               System.out.println(image);
          } catch (Exception e) {
               e.printStackTrace();
     private static String uploadToIs(String fffffile) {
          HttpURLConnection conn = null;
          DataOutputStream dos = null;
          DataInputStream inStream = null;
          String lineEnd = "\r\n";
          String twoHyphens = "--";
          String boundary = "*****";
          int bytesRead, bytesAvailable, bufferSize;
          byte[] buffer;
          int maxBufferSize = 1 * 1024 * 1024;
          String urlString = "http://www.imageshack.us";
          try {
               String strFilename = fffffile;
               try {
                    FileInputStream fileInputStream = new FileInputStream(new File(
                              strFilename));
                    URL url = new URL(urlString);
                    conn = (HttpURLConnection) url.openConnection();
                    conn.setDoInput(true);
                    conn.setDoOutput(true);
                    conn.setUseCaches(false);
                    conn.setRequestMethod("POST");
                    conn.setRequestProperty("Connection", "Keep-Alive");
                    conn.setRequestProperty("Content-Type",
                              "multipart/form-data;boundary=" + boundary);
                    dos = new DataOutputStream(conn.getOutputStream());
                    dos.writeBytes(twoHyphens + boundary + lineEnd);
                    dos
                              .writeBytes("Content-Disposition: form-data; name=\"fileupload\";"
                                        + " filename=\"" + strFilename + "\"" + lineEnd);
                    dos.writeBytes(lineEnd);
                    bytesAvailable = fileInputStream.available();
                    bufferSize = Math.min(bytesAvailable, maxBufferSize);
                    buffer = new byte[bufferSize];
                    bytesRead = fileInputStream.read(buffer, 0, bufferSize);
                    while (bytesRead > 0) {
                         dos.write(buffer, 0, bufferSize);
                         bytesAvailable = fileInputStream.available();
                         bufferSize = Math.min(bytesAvailable, maxBufferSize);
                         bytesRead = fileInputStream.read(buffer, 0, bufferSize);
                    dos.writeBytes(lineEnd);
                    dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);
                    fileInputStream.close();
                    dos.flush();
                    dos.close();
               } catch (MalformedURLException ex) {
                    System.out.println("Got a malformed URL:" + ex);
               } catch (IOException ioe) {
                    System.out.println("Got an IO issue:" + ioe);
          } catch (Exception e) {
               System.out
                         .println("Sorry, could not find the file to upload. Skipping...");
          try {
               inStream = new DataInputStream(conn.getInputStream());
               int ii;
               String returnd = "";
               while ((ii = inStream.read()) != -1) {
                    returnd += (char) ii;
               int pos = returnd.indexOf("Include details");
               returnd = returnd.substring(pos);
               pos = returnd.indexOf("[IMG]");
               returnd = returnd.substring(pos + 5);
               pos = returnd.indexOf("[/IMG]");
               returnd = returnd.substring(0, pos);
               inStream.close();
               return (returnd);
          } catch (IOException ioex) {
               System.out
                         .println("Got an IO issue from (ServerResponse): " + ioex);
          return "";
}When I start the thread by doing:
new Screenshot().start();I get the String index out of range: -1 error.
StackTrace:
java.lang.StringIndexOutOfBoundsException: String index out of range: -1
     at java.lang.String.substring(Unknown Source)
     at java.lang.String.substring(Unknown Source)
     at Screenshot.uploadToIs(Screenshot.java:93)
     at Screenshot.run(Screenshot.java:23)
But when I add a main method into that class and start the thread it runs fine.
I would appritiate help, thanks alot:)

Answer 1

I understand that part, I was just wondering why my string isn't read when I try and start the thread from another class, but when I run this class on its own and start the thread, it runs fine..