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Difference Between Enumeration VS Iterator VS ListIterator in Java

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In this article, we will compare 3 important cursors Enumeration, Iterator & ListIterator in detail i.e.; Enumeration v/s Iterator v/s ListIterator interfaces. All 3 cursors are used to iterate over collection items, but there are certain differences between each one of them

So lets us discuss in Details;

Enumeration vs Iterator vs ListIterator

Enumeration

Iterator

ListIterator
This is part of Legacy collection introduced in Java 1.0 version This is part of Collection framework introduced in Java 1.2 version This is part of Collection framework introduced in Java 1.2 version
Using Enumeration interface, we can enumerate only legacy classes like Hashtable or Vector or Properties Iterator interface is applicable for every collection classes like ArrayList, HashSet or Hashtable ListIterator interface is applicable only for List objects like ArrayList or LinkedList or Vector
We can enumerate legacy collection items only in a FORWARD direction Here, too we can iterate through collection items only in a FORWARD direction But with ListIterator, we can iterate through list items either in Forwarding or BACKWARD directions
That is, it is a unidirectional or single-directional cursor That is, it is a unidirectional or single-directional cursor That is, it is a bi-directional cursor
Using Enumeration interface, we can enumerate to read or get element/object from a legacy collection Using Iterator interface, we can read as well as remove collection items, while iterating Addition or replacement of new objects is possible alongside reading and remove operation in ListIterator interface
To get an Enumeration object, we can use elements() method of any legacy collection class example,

Vector v = new Vector();
Enumeration e = v.elements();

 To get an Iterator object, we can use iterator() method of any collection class example,

Iterator it = col.iterator();
Where col = any collection class

 To get a ListIterator object, we can use listIterator() method of any List classes for example,

ListIterator ltr = list.listIterator();
Where list = any List objects
This interface has 2 important methods to enumerate through the legacy collection object:

  • hasMoreElements();
  • nextElement();
 Iterator interface has 3 important methods to iterate through any collection object boolean

  • hasNext();
  • Object next();
  • void remove();
 ListIterator interface has 9 important methods to iterate through any

  • add()
  • hasNext()
  • hasPrevious()
  • next()
  • nextIndex()
  • previous()
  • previousIndex()
  • remove()
  • set()

Best practice:

Enumeration interface:

  • Use this cursor only with a legacy collection, to work with a thread-safe environment

Iterator interface:

  • This is very popular among 3 cursors, as it is applicable for any collection class

ListIterator interface:

  • Again, this is applicable only for List objects.
  • Use this cursor, to benefit from iterating through List items in both directions
  • i.e.; both FORWARD & BACKWARD directions

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