Java: ArrayList Vs Vector Class


java.util.ArrayList and java.util.Vector both implements List interface and maintains insertion order. It’s having many differences as below:

ArrayList vs Vector

ArrayList Vector
ArrayList is not synchronized. Vector is synchronized.
ArrayList increases 50% of the current array size if the number of elements exceeds its capacity. Vector increase 100% means doubles the array size when the total number of elements exceeds its capacity.
ArrayList is not a legacy class. It is introduced in JDK 1.2. Vector is a legacy class.
ArrayList is fast because it is non-synchronized. Vector is slow because it is synchronized, i.e., in a multithreading environment, it holds the other threads in the runnable or non-runnable state until the current thread releases the lock of the object.
ArrayList uses the Iterator interface to traverse the elements. A Vector can use the Iterator interface or Enumeration interface to traverse the elements.
See Also:ArrayList Class See Also:Java: Vector Class

ArrayList Example: traversing by the iterator

import java.util.*;
class ArrayListExample{
 public static void main(String args[]){    

  //creating arraylist of String
  List al=new ArrayList();
 //adding objecta in arraylist
  al.add("Saurabh");
  al.add("Mahesh");
  al.add("Jonny");
  al.add("Anil");
  //traverse elements using Iterator
  Iterator itr=al.iterator();
  while(itr.hasNext()){
   System.out.println(itr.next());
  }
 }
}

Output

Saurabh
Mahesh
Jonny
Anil

Vector Example: Traversing by Enumerator

import java.util.*;
class VectorExample{
 public static void main(String args[]){
  Vector v=new Vector();//creating vector
  v.add("Umrao");//method of Collection
  v.addElement("Isha");//method of Vector
  v.addElement("Kush");
  //traverse elements using Enumeration
  Enumeration e=v.elements();
  while(e.hasMoreElements()){
   System.out.println(e.nextElement());
  }
 }
}

Output

Umrao
Isha
Kush

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