Codigo para verificar se um email informado é valido

String regex = "(\\w+)@(\\w+\\.)(\\w+)(\\.\\w+)*";
String email = "[email removido]";

if(email.matches(regex)){
   System.out.println("Oba é valido!");
}else{
   System.out.println("Não é valido!");
}

function checkEmail(emailStr) {
    if (emailStr.length == 0) {
        return true;
    }
    var emailPat=/^(.+)@(.+)$/;
    var specialChars="\\(\\)<>@,;:\\\\\\\"\\.\\[\\]";
    var validChars="\[^\\s" + specialChars + "\]";
    var quotedUser="(\"[^\"]*\")";
    var ipDomainPat=/^(\d{1,3})[.](\d{1,3})[.](\d{1,3})[.](\d{1,3})$/;
    var atom=validChars + '+';
    var word="(" + atom + "|" + quotedUser + ")";
    var userPat=new RegExp("^" + word + "(\\." + word + ")*$");
    var domainPat=new RegExp("^" + atom + "(\\." + atom + ")*$");
    var matchArray=emailStr.match(emailPat);
    if (matchArray == null) {
        return false;
    }
    var user=matchArray[1];
    var domain=matchArray[2];
    if (user.match(userPat) == null) {
        return false;
    }
    var IPArray = domain.match(ipDomainPat);
    if (IPArray != null) {
        for (var i = 1; i <= 4; i++) {
           if (IPArray[i] > 255) {
              return false;
           }
        }
        return true;
    }
    var domainArray=domain.match(domainPat);
    if (domainArray == null) {
        return false;
    }
    var atomPat=new RegExp(atom,"g");
    var domArr=domain.match(atomPat);
    var len=domArr.length;
    if ((domArr[domArr.length-1].length < 2) ||
        (domArr[domArr.length-1].length > 3)) {
        return false;
    }
    if (len < 2) {
        return false;
    }
    return true;
 }