previous | start | next

---

More About Objects

• The root class of the Java class hierarchy is Object _(doc) .
• To create a copy of an object, use Object's clone() method.
  

  protected Object clone()
                 throws CloneNotSupportedException
  

• Library objects generally implement clone(). Example: create a copy of a Date _(doc) object:
  

  // new Date object with current time
  Date dateNow = new Date();               
  ...
  // create identical copy of nowDate
  Date dateCopy = (Date) dateNow.clone();  
  

  dateNow and dateCopy reference each a different object,
  but with the same data. Uses cast because clone returns Object reference.
  
• Custom objects should implement (override) clone().

---

previous | start | next