I am sending an object with some primitive fields using Restlet with Jackson converter. Up until now it worked great. But then I needed my object to implement Serializable, because I need to store it in memcache of GAE. For some reason - when the class implements Serializable, things stop working. Restlet sends a different string representation from before, and I can't even print that string in the server. I tried printing its byte value, char-by-char and the first numbers are: 0xfffd 0xfffd 0x0000 0x0005 0x0073 0x0072 Thanks a lot!