How to check if a given Regex is valid?

Question

I have a little program allowing users to type-in some regular expressions. afterwards I like to check if this input is a valid regex or not.

I\'m w

Answer 1

public class Solution {
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        int testCases = Integer.parseInt(in.nextLine());
        while(testCases>0){
            String pattern = in.nextLine();
            try{
                Pattern.compile(pattern);
                System.out.println("Valid");
            }catch(PatternSyntaxException exception){
                System.out.println("Invalid");
            }

        }
    }
}