posted 9 years ago
Some libraries expect types to be Serializable in order to transform them to different formats, such as XML, JSON or database entries. For large object graphs, it can also be relatively quick to make all involved objects Serializable when you want to write them to a file.
In general though, I don't think the cost is worth it. Making a type Serializable means you have to think about a *lot* of things that can possibly go wrong, and it's easy to make mistakes in your implementation.
Most of the time I prefer to make "repository types" that are responsible for storing my objects somewhere, usually using a BufferedWriter to write them to a simple text file.