Java Pattern and Matcher working in app but not in webservice

I have a java regex (to validate an email address although this is not what my question is about) which works in an standard java app however when I put that same code into a restful web service it no longer works. The code in the app looks as follows:

public static void main(String[] args) {
    List <String> emails = new ArrayList();
    emails.add("user@domain.com");
    emails.add("user@domain.co.in");

    //Invalid emails
    emails.add(".username@yahoo.com");
    emails.add("username@yahoo.com.");

    String regex = "^[\\w!#$%&'*+/=?`{|}~^-]+(?:\\.[\\w!#$%&'*+/=?`{|}~^-]+)*@(?:[a-zA-Z0-9-]+\\.)+[a-zA-Z]{2,6}$";

    Pattern pattern = Pattern.compile(regex);

    for(String email : emails){
        Matcher matcher = pattern.matcher(email);
        System.out.println(email +" : "+ matcher.matches());
    }
}

This example has been shamelessly copied from here

This actually works fine for my purpose. However when I try to include that same pattern and matcher into a web service I always get a false match. My attempt looks as follows:

@GET
@Path("/{i}")
@Produces(MediaType.APPLICATION_JSON)
public Response getData( @PathParam("i") String eMailAddress_ ) {
    String returnStr;

    String regex = "^[\\\\w!#$%&'*+/=?`{|}~^-]+(?:\\\\.[\\\\w!#$%&'*+/=?`{|}~^-]+)*@(?:[a-zA-Z0-9-]+\\\\.)+[a-zA-Z]{2,6}$";
    Pattern pattern = Pattern.compile(regex);
    Matcher matcher = pattern.matcher(eMailAddress_);

    if (matcher.matches()) {
        returnStr = eMailAddress_ + " is VALID";
    }
    else {
        returnStr = eMailAddress_ + " is INVALID";
    }

    return Response.ok("{\"Result\":\"" + returnStr + "\"}", MediaType.APPLICATION_JSON).build();
}

Now if I send user@domain.com on the url the response I get in return from the matcher is FALSE.

I have even tried to hard code eMailAddress_ to be user@domain.com in the webservice so that no matter what parameter I pass the webservice applies the matcher to that hard coded value which I know validates to TRUE in the first app however I still get the matcher returning FALSE.

I am using netbeans 8.2 on java 1.8.