# Shallow copy vs Deep Copy
**memento:** a saved snapshot of the state of an object for possible later use
**Shallow copy:** copy just primitive data types
1. make the class implements the clonable interface
2. override method clone (Make it public)
3. when you want to copy an object just call the clone method

**Deep copy:** copy the object with all inner objects
**how do we can perform deep copy?**
by saving the object into a file and then read into another object.
4. make the class and all inner classes implements Serializable interface.

// write
  FileOutputStreem fos = new FileOutputStreem();
  ObjectOutputStreem oos = new ObjectOutputStreem (fos);
oos.writeObject(object1);

// read
FileInputStreem fis = new FileInputStreem (path);
ObjectInputStreem ois = new ObjectInputStreem (fis)
Object2 object2 = ois.readObject();

if you have some attribute you don't want to copy use **"transient"** keyword