The problem is that you're transforming a byte array output stream to a String using toString()
. The toString()
method simply uses the platform default encoding to transform the bytes (which do not represent characters at all but are purely binary data) into a String. This is thus a lossy operation, because your platform default encoding doesn't have a valid character for every possible byte.
You shouldn't use String to hold binary data. A String contains characters. If you really need a String, then encode the byte array using a Hexadecimal or Base64 encoder. Otherwise, simply use a byte array to hold your binary data:
public static byte[] serialize(Quiz quiz) throws IOException{
...
ByteArrayOutputStream baos = new ByteArrayOutputStream();
...
return baos.toByteArray();
}
@SuppressWarnings("unchecked")
public static Quiz deserialize(byte[] serializedQuizData) throws IOException, ClassNotFoundException{
ByteArrayInputStream bais = new ByteArrayInputStream(serializedQuizData);
...
return quiz;
}