Deep Cloning

• Why doesn't clone make a deep copy?
  Wouldn't work for cyclic data structures
  
• Shared structure not a problem for immutable fields
• You must clone mutable fields
  

public class Employee 
  implements Cloneable 
{ 
   public Employee clone() 
   { 
      try 
      { 
         Employee cloned = (Employee)super.clone();
         cloned.hireDate = (Date)hiredate.clone();
         return cloned; 
      } 
      catch(CloneNotSupportedException e) 
      { 
         return null; // won't happen 
      }
   } 
   ... 
}