public void testIsEmailValid() { boolean isValid = false; //Initialize reg ex for email. String expression = "^\\(([a-zA-Z0-9 _\\-\\.\\+]+)\\)\\ ([a-zA-Z0-9\n" + "_\\!\\#\\$\\%\\&\\'\\*\\-\\/\\=\\?\\^\\`\\{\\|\\}\\~\\.]+)@((\\[[0-9]{1,3}\\.[0-9]{1,3}\\\n" + ".[0-9]{1,3}\\.)|(([a-zA-Z0-9\\w\n" + "_\\!\\#\\$\\%\\&\\'\\*\\-\\/\\=\\?\\^\\`\\{\\|\\}\\~]+\\.)+))([a-zA-Z]{2,4}|[0-9]{1,3}\n" + ")$|^([a-zA-Z0-9 \\w\n" + "_\\!\\#\\$\\%\\&\\'\\*\\-\\/\\=\\?\\^\\`\\{\\|\\}\\~\\.]+)@((\\[[0-9]{1,3}\\.[0-9]{1,3}\\\n" + ".[0-9]{1,3}\\.)|(([a-zA-Z0-9_\\-]+\\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})$"; CharSequence inputStr ="name.su$rname@$blah.com"; //This will fail CharSequence inputStr2 ="name.su$rname@blah.com"; //This will pass validation //Make the comparison case-insensitive. Pattern pattern = Pattern.compile(expression, Pattern.CASE_INSENSITIVE); Matcher matcher = pattern.matcher(inputStr2); if (matcher.matches()) { isValid = true; } System.out.println("is Valid ::: " + isValid); }