Effective Java - Chapter 11 Serialization

defaultReadObject/defaultWriteObject

1. Serialization
   - serialized form and UID
   - another constructor
   - 提供parameterless constructor以便subclass可以serializable, 用AtomicReference確保subclass有正確的initiate
   
   
2. Use a custom serialized form
   - don't use default without consideration
   - 只寫出logic representation
   - 通常custom會較快
   - always invoke defaultReadObject/defaultWriteObject
   - Hashtable的default form甚至會error !!
   - always use serial version UID
   
3. Write readObject methods defensively
4. Use enum to instance control
5. 當需要自己寫readObject/writeObject時, 可考慮使用Serialization Proxy