Extract a part from a txt file

Question

Hi, I've a simple problem which unfortunately can not solve.
I have some txt's that I want only to extract a part o them. (The first 100 characters). Here is my code:
import java.io.*;
public class ReadSource {
     public static void main(String[] arguments) {
        try {
          FileReader file = new FileReader("1.txt");
          BufferedReader buff = new BufferedReader(file);
           boolean eof = false;
           while (!eof) {
                String line = buff.readLine();
                if (line == null)
                    eof = true;
                 else{
                 int start = line.indexOf("something");
                 int end = line.indexOf("something_else");
                 String str2 = line.substring(start, end);
                  System.out.println(str2);
            buff.close();
        } catch (IOException e) {
            System.out.println("Error -- " + e.toString());
}and the error tha java displays is:
java.lang.StringIndexOutOfBoundsException: String index out of range: -1
     at java.lang.String.substring(String.java:1438)
     at ReadSource.main(ReadSource.java:21)
Exception in thread "main"

Answer 1

Tim I'm very sorry but is still don't work. It still display the same error.
Look at my code
import java.io.*;
public class ReadSource {
     public static void main(String[] arguments) {
       try {
               BufferedReader reader = new BufferedReader(new FileReader("1.txt"));
               BufferedWriter writer = new BufferedWriter(new StringWriter());
               String line = null;
               while ((line = reader.readLine()) != null) {
                   writer.write(line);
                   writer.newLine();
               String content = writer.toString();
               // Now you have the whole file content into the content String
               int start = content.indexOf("smth");
               int end = content.indexOf("smth2");
               String str2 = content.substring(start,end);
               System.out.println("start = "+start+", end = "+end);
               System.out.println(str2);
           reader.close();
     }catch (IOException e) {
            System.out.println("Error -- " + e.toString());
}It looks very logical, I don't know what happens
Thank you very much for your help.
Kostas