Extracting A String From HTML Source Code?

I want to extract a specific String from HTML, specifically, I want to extract a String from in between <...>

So far, I've got this

package main;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
public class HTMLGrabber {
static String allOneString = "";

[code]....

The problem I have is when I change the last parameter in this line:

System.out.println("And the Keywords are:

" +allOneString.substring(allOneString.lastIndexOf("meta name="keywords" content=") + 30, allOneString.indexOf("Fictional History">")+17));

to

System.out.println("And the Keywords are:

" +allOneString.substring(allOneString.lastIndexOf("meta name="keywords" content=") + 30, allOneString.indexOf("">")));

i.e. the generic alternative, I get this error message:

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: -366
at java.lang.String.substring(Unknown Source)
at main.HTMLGrabber.main(HTMLGrabber.java:45)

Is there a better and simple way to extract a substring?