1. 避免Serialize Inner Class, 见oracle文档：“Serialization of inner classes (i.e., nested classes that are not static member classes), including local and anonymous classes, is strongly discouraged for several reasons. Because inner classes declared in non-static contexts contain implicit non-transient references to enclosing class instances, serializing such an inner class instance will result in serialization of its associated outer class instance as well. ”;
2. 所有的non-static或none-transient非基本类型域, 都应该implements Serializable;
3. 明确使用private final static关键字，指定serialVersionUID。如果不指定，不同虚拟机可能计算出不同默认serialVersionUID, 产生难以意料的问题
4. new versions of Serializable classes may or may not be able to read old serialized objects; it depend on the nature of the changes. 见：Type Changes Affecting Serialization