問題：
Eclipse issues warnings when a serialVersionUID is missing. Eclipse 會在缺少serialVersionUID時發出警告。
The serializable class Foo does not declare a static final serialVersionUID field of type long可序列化類 Foo 未聲明 long 類型的靜態最終 serialVersionUID 字段
What is serialVersionUID and why is it important?什麼是serialVersionUID ，爲什麼它很重要？ Please show an example where missing serialVersionUID will cause a problem.請舉例說明缺少serialVersionUID會導致問題的地方。
解決方案：
參考一： https://stackoom.com/question/1CLZ參考二： What is a serialVersionUID and why should I use it?