Behaviour of find() in Matcher class

[Branislav Devrnja]

Hi,
I was doing one exercise from SCJP book,
and I don't understand why find() in a loop goes past the end of source string,
in this example, i.e it seems to return true at index 6 but source string's last index is 5 so even after the last character in string find() once more returns true - at index 6, beyond source end- what is the explanation for such behavior?
The output is:
01234456
i: 6

Thanks
Branislav

package certification;
import java.util.regex.*;
class Regex2 {
 
/**
 * @param args
 */
public static void main(String[] args) {
String s0 = "\\d*", s1 = "ab34ef";
Pattern p = Pattern.compile(s0);
Matcher m = p.matcher(s1);
boolean b = false;
int i = 0;
while (b = m.find()) {
System.out.print(m.start()+ m.group());
i++;
}
System.out.println("\ni: "+i);
}
 
}    

[Rob Spoor]

This question has been asked (and answered) multiple times already in the SCJP forum. I'm moving this thread there.

[Henry Wong]

http://faq.javaranch.com/java/ScjpFaq#kb-regexp