Add the missing code: import java.util.Scanner;

public class StringChecker $\{$

public static void main$($String$[]$ args$)\{$

Scanner scnr $=$ new Scanner$($System$.$in$)$;

String userString;

if $($isValid$)\{$

System.out.println$("$String accepted"$)$;

$\}$

else $\{$

System.out.println$("$String not accepted"$)$;

$\}$

$\}$

$\}$