How to extract a group from a Java String that contains a Regex pattern

How to extract a group from a Java String that contains a Regex pattern

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class RegexTest {
   public static void main(String[] args) {
      Pattern pattern = Pattern.compile("fun");
      Matcher matcher = pattern.matcher("Java is fun");

      // using Matcher find(), group(), start() and end() methods
      while (matcher.find()) {
         System.out.println("Found the text \"" + matcher.group()
            + "\" starting at " + matcher.start()
            + " index and ending at index " + matcher.end());
      }
   }
}

check if a string contains numbers or not using Java regex.

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Numberornot {
   public static void main(String[] args) {
      String s;
      System.out.println("enter string");
      Scanner sc=new Scanner(System.in);
      s = sc.nextLine();
      System.out.println(isNumber(s));
   }
   public static boolean isNumber( String s ) {
      Pattern p = Pattern.compile( "[0-9]" );
      Matcher m = p.matcher( s );
      return m.find();
   }
}

Output

enter string
hello123
true

Output

enter string
hello
false