原型模式中的拷贝分为"浅拷贝"和"深拷贝":

浅拷贝: 对值类型的成员变量进行值的复制,对引用类型的成员变量只复制引用,不复制引用的对象.

深拷贝: 对值类型的成员变量进行值的复制,对引用类型的成员变量也进行引用对象的复制.

关于Object类的clone方法：

The method clone for class Object performs a specific cloning operation. First, if the class of this object does not implement the interface Cloneable, then a CloneNotSupportedException is thrown. Note that all arrays are considered to implement the interface Cloneable. Otherwise, this method creates a new instance of the class of this object and initializes all its fields with exactly the contents of the corresponding fields of this object, as if by assignment; the contents of the fields are not themselves cloned. Thus, this method performs a "shallow copy" of this object, not a "deep copy" operation. 

默认实现为“浅拷贝”，请注意。

实现“深拷贝”时，clone()方法中该类的引用类型的成员变量要给个新对象。

关于java.lang.Cloneable接口：

A class implements the Cloneable interface to indicate to the java.lang.Object.clone() method that it is legal for that method to make a field-for-field copy of instances of that class.

Invoking Object's clone method on an instance that does not implement the Cloneable interface results in the exception CloneNotSupportedException being thrown.