How to use try and catch in Error Handling?

Try and catch in Error Handling
It is possible for a script to use multiple exceptions to check for multiple conditions.
It is possible to use several if..else blocks, a switch, or nest multiple exceptions. These exceptions can use different exception classes and return different error messages:
<?php
class myException extends Exception {
  public function errorMessage() {
    $errMsg= 'Error on line '.$this->getLine().' in '.$this->getFile()
    .': <b>'.$this->getMessage().'</b> is not a valid EMail address';
    return $errMsg;
  }
}

$email = "sagar@domain...com";

try {
  //check if
  if(filter_var($email, FILTER_VALIDATE_EMAIL) === FALSE) {
    //throw exception if email is not valid
    throw new myException($email);
  }
  //check for "example" in mail address
  if(strpos($email, "example") !== FALSE) {
    throw new Exception("$email is an example e-mail");
  }
}

catch (myException $e) {
  echo $e->errorMessage();
}

catch(Exception $e) {
  echo $e->getMessage();
}
?>