import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Main {
public static void main(String[] args) {
String patternStr = "b";
Pattern pattern = Pattern.compile(patternStr);
CharSequence inputStr = "a b c b";
Matcher matcher = pattern.matcher(inputStr);
boolean matchFound = matcher.find();
System.out.println(matchFound);
String match = matcher.group();
System.out.println(match);
int start = matcher.start();
int end = matcher.end();
System.out.println(start);
System.out.println(end);
matchFound = matcher.find();
}
}