import java.util.regex.Matcher;
import java.util.regex.Pattern;
 
public class Main
{
    public static void main(String a[]){
        String stream = "ab34ef";
        Pattern pattern = Pattern.compile("\\d*");
 
        //HERE * IS GREEDY QUANTIFIER THAT LOOKS FOR ZERO TO MANY COMBINATION THAT 
        //START WITH NUMBER 
        Matcher matcher = pattern.matcher(stream);
 
        while(matcher.find()){
            System.out.println(matcher.start()+ ": " + matcher.group());
        }
    }
}
 

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