question: public static boolean isEmailIdValid ( String email ) { String expression = "^[\\w\\.-]+@([\\w\\-]+\\.)+[A-Z]{2,4}$" ; Pattern pattern = Pattern . compile ( expression , Pattern . CASE_INSENSITIVE ) ; Matcher matcher = pattern . matcher ( email ) ; return matcher . matches ( ) ; }
target:  check the email address is valid or not.