vector

The Vector class implements a growable array of objects. Like an array, it contains components that can be accessed using an integer index. However, the size of aVector can grow or shrink as needed to accommodate adding and removing items after the Vector has been created.

Each vector tries to optimize storage management by maintaining a capacity and a capacityIncrement. The capacity is always at least as large as the vector size; it is usually larger because as components are added to the vector, the vector's storage increases in chunks the size of capacityIncrement. An application can increase the capacity of a vector before inserting a large number of components; this reduces the amount of incremental reallocation.

As of the Java 2 platform v1.2, this class has been retrofitted to implement List, so that it becomes a part of Java's collection framework. Unlike the new collection implementations, Vector is synchronized.

import java.util.*;
class co
{
     public static void main(String arg[])
     {
         Vector v=new Vector();
         v.addElement("a");
         for(int i=0;i<10;i++)
         {
        v.addElement(new Integer(i));
         }
         System.out.println(v);
         System.out.println(v.capacity()); // 10
         v.add("b");
         System.out.println(v.capacity()); // 20
    }
}

******************************************************************

import java.util.*;

class co1

{

 public static void main(String[] args)

 {

     ArrayList a1=new ArrayList();

 

         a1.add(new Integer(10));

         a1.add("hello");

         a1.add(new Integer(20*5));

         a1.add(new Integer(30));

     System.out.println(a1);  // here ArryList toString method called

     // By using  iterator

 

     Iterator i1=a1.iterator();

     while(i1.hasNext())

             System.out.println(i1.next());

          

         }

}

*****************************************************************************

 import java.util.ArrayList; 

public class co2 

{  public static void main(String[] args)

 {  

  //create an ArrayList object  

 ArrayList arrayList = new ArrayList();

//Add elements to Arraylist    

arrayList.add("1");

arrayList.add("2");

arrayList.add("3");

/*      To add an element at the specified index of ArrayList use      void add(int index, Object obj) method.      This method inserts the specified element at the specified index in the      ArrayList.      */   

 arrayList.add(1,"INSERTED ELEMENT");    

 /*      Please note that add method DOES NOT overwrites the element previously      at the specified index in the list. It shifts the elements to right side      and increasing the list size by 1.    */    

System.out.println("ArrayList contains...");    

//display elements of ArrayList    

for(int index=0; index < arrayList.size(); index++)   

System.out.println(arrayList.get(index));  

 }

}

***********************************************************************

//AppendAllElementsOfOtherCollectionToArrayListExample

import java.util.ArrayList;

import java.util.Vector;

public class co3  

{   

public static void main(String[] args) 

{ 

 //create an ArrayList object

ArrayList arrayList = new ArrayList();     

//Add elements to Arraylist    

arrayList.add("1");    

arrayList.add("2");    

arrayList.add("3");     

//create a new Vector object    

Vector v = new Vector();    

v.add("4");    

v.add("5");     

/*      To append all elements of another Collection to ArrayList use      boolean addAll(Collection c) method.      It returns true if the ArrayList was changed by the method call.    */     

//append all elements of Vector to ArrayList    

arrayList.addAll(v);     

//display elements of ArrayList    

System.out.println("After appending all elements of Vector, ArrayList contains..");    

for(int i=0; i<arrayList.size(); i++)      

System.out.println(arrayList.get(i));   

}} 

/*Output would beAfter appending all elements of Vector, ArrayList contains..12345*/

**********************************************************************************

//CopyElementsOfArrayListToArrayExample

import java.util.ArrayList; 

public class  co4

{   

public static void main(String[] args) 

{    

//create an ArrayList object   

 ArrayList arrayList = new ArrayList();     

//Add elements to ArrayList    

arrayList.add("1");    

arrayList.add("2");    

arrayList.add("3");    

arrayList.add("4");    

arrayList.add("5");     

/*      To copy all elements of java ArrayList object into array use      Object[] toArray() method.    */     

Object[] objArray = arrayList.toArray();     

//display contents of Object array    

System.out.println("ArrayList elements are copied into an Array.                                                    Now Array Contains..");    

for(int index=0; index < objArray.length ; index++)      System.out.println(objArray[index]);  }}

**********************************************************************************

//GetSizeOfArrayListExample 

import java.util.ArrayList; 

public class co5

{   

public static void main(String[] args) 

{  

 //create an ArrayList object    

ArrayList arrayList = new ArrayList();     

//Add elements to Arraylist using    

arrayList.add("1");    

arrayList.add("2");    

arrayList.add("3");     

//To get size of Java ArrayList use int size() method    

int totalElements = arrayList.size();     

System.out.println("ArrayList contains...");    

//loop through it    

for(int index=0; index < totalElements; index++)      System.out.println(arrayList.get(index));   

}

}

************************************************************************

//GetSubListOfJavaArrayListExample

import java.util.ArrayList;

import java.util.List; 

public class  co6

{   

public static void main(String[] args) 

{     

//create an ArrayList object    

ArrayList arrayList = new ArrayList();     

//Add elements to Arraylist    

arrayList.add("1");    

arrayList.add("2");    

arrayList.add("3");    

arrayList.add("4");    

arrayList.add("5");     

/*       To get a sub list of Java ArrayList use       List subList(int startIndex, int endIndex) method.       This method returns an object of type List containing elements from       startIndex to endIndex - 1.    */     

List lst = arrayList.subList(1,3);    

 //display elements of sub list.    

System.out.println("Sub list contains : ");    

for(int i=0; i< lst.size() ; i++)    

 System.out.println(lst.get(i));    

 /*      Sub List returned by subList method is backed by original Arraylist. So any      changes made to sub list will also be REFLECTED in the original Arraylist.    */  

  //remove one element from sub list    

Object obj = lst.remove(0);    

System.out.println(obj + " is removed from sub list");    

 //print original ArrayList    

System.out.println("After removing " + obj + " from sub list, original ArrayList contains : ");    for(int i=0; i< arrayList.size() ; i++)      

System.out.println(arrayList.get(i)); 

  }

}