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

new String().matches(regEx) can be directly be used with try-catch to identify if regEx is valid.

boolean isValidRegEx = true;
try {
    new String().matches(regEx);
} catch(PatternSyntaxException e) {
    isValidRegEx = false;
}