title: Validation of regex input through json schema
body: <p>I have to accept a <code>regular expression</code> as an input from user  from html page. I am using spring boot for backend with json schema validation</p>
  <p><code>Pattern.compile(regex);</code></p>
  <p>method in java as backend, will throw an error if it is not valid regex. This will not throw any error if it is a valid regex.</p>
  <p>Can we do the same thing with json schema for validating regex input without using dynamic method in java?(So that number of test cases can be reduced)</p>
  <p>How can we acheive this with just json schema?</p>