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