Here I have created a Email validation function .By used this function we can check user input value like example (sachin@gmail.com)in this example validation function checked string value are proper format or not .In my below code I have clearly describe how to make Email validation function.

public class EmailValidator {

    private Pattern pattern;
    private Matcher matcher;

    private static final String EMAIL_PATTERN =
            "^[_A-Za-z0-9-\\+]+(\\.[_A-Za-z0-9-]+)*@"
                    + "[A-Za-z0-9-]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$";

    public EmailValidator() {
        pattern = Pattern.compile(EMAIL_PATTERN);
    }


    public boolean validate(final String email) {

        matcher = pattern.matcher(email);
        return matcher.matches();

    }
}