Here you can find the source of isEmail(CharSequence input)
public static synchronized final boolean isEmail(CharSequence input)
//package com.java2s; //License from project: Apache License import java.util.regex.Pattern; public class Main { private static Pattern email_Pattern = Pattern.compile( "^([\\w-\\.]+)@((\\[[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.)|(([\\w-]+\\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\\]?)$"); public static synchronized final boolean isEmail(CharSequence input) { return email_Pattern.matcher(input).matches(); }//from w ww . ja v a2 s. co m }