Base64: java.lang.IllegalArgumentException: Illegal character
base64, jakarta-mail, java, registration
Solution
Your encoded text is `[B@6499375d`. That is not Base64, something went wrong while encoding. That decoding code looks good.
Use this code to convert the byte[] to a String before adding it to the URL:
String encodedEmailString = new String(encodedEmail, "UTF-8");
// ...
String confirmLink = "Complete your registration by clicking on following"
+ "\n<a href='" + confirmationURL + encodedEmailString + "'>link</a>";
Problem
I'm trying to send a confirmation email after user registration. I'm using the JavaMail library for this purpose and the Java 8 Base64 util class. I'm encoding user emails in the following way: ``` byte[] encodedEmail = Base64.getUrlEncoder().encode(user.getEmail().getBytes(StandardCharsets.UTF_8)); Multipart multipart = new MimeMultipart(); InternetHeaders headers = new InternetHeaders(); headers.addHeader("Content-type", "text/html; charset=UTF-8"); String confirmLink = "Complete your registration by clicking on following"+ "\n<a href='" + confirmationURL + encodedEmail + "'>link</a>"; MimeBodyPart link = new MimeBodyPart(headers, confirmLink.getBytes("UTF-8")); multipart.addBodyPart(link); ``` where `confirmationURL` is: ``` private final static String confirmationURL = "http://localhost:8080/project/controller?command=confirmRegistration&ID="; ``` And then decoding this in ConfirmRegistrationCommand in such way: ``` String encryptedEmail = request.getParameter("ID"); String decodedEmail = new String(Base64.getUrlDecoder().decode(encryptedEmail), StandardCharsets.UTF_8); RepositoryFactory repositoryFactory = RepositoryFactory .getFactoryByName(FactoryType.MYSQL_REPOSITORY_FACTORY); UserRepository userRepository = repositoryFactory.getUserRepository(); User user = userRepository.find(decodedEmail); if (user.getEmail().equals(decodedEmail)) { user.setActiveStatus(true); return Path.WELCOME_PAGE; } else { return Path.ERROR_PAGE; } ``` And when I'm trying to decode: ``` http://localhost:8080/project/controller?command=confirmRegistration&ID=[B@6499375d ``` I'm getting `java.lang.IllegalArgumentException: Illegal base64 character 5b`. I tried to use basic Encode/Decoder (not URL ones) with no success. SOLVED: The problem was the next - in the line: ``` String confirmLink = "Complete your registration by clicking on following"+ "\n<a href='" + confirmationURL + encodedEmail + "'>link</a>"; ``` I'm calling toString on an array of bytes, so I should do the following: ``` String encodedEmail = new String(Base64.getEncoder().encode( user.getEmail().getBytes(StandardCharsets.UTF_8))); ``` Thanks to Jon Skeet and ByteHamster.