It's actually almost the exact same:
Base64 decoder = new Base64();
byte[] saltArray = decoder.decode(saltD);
byte[] ciphertextArray = decoder.decode(ciphertext);
For decoding:
String saltString = encoder.encodeToString(salt);
String ciphertextString = encoder.encodeToString(ciphertext);
This last one was tougher because you use "toString" at the end.