ArrayList Class Collection example java

ArrayList Class

An ArrayList is like an array, which can grow in memory dynamically.Memory is dynamically allotted and re-allotted to accommodate all the elements. ArrayList is not synchronized. Un-reliable result in case of multi threading.

Default Initial Capacity: 10
Load Factor=0.75

ArrayList Class Methods

• boolean add(element obj)
• void add(int position,element obj)
• element remove(int position)
• boolean remove(object obj)
• void clear()
• element set(int position,element obj)
• boolean contains(Object obj)
• element get(int position)
• int indexOf(Object obj)
• int lastIndexOf(Object obj)
• int size()
• Object[] toArray()

Program:

/**

 * 

 */

package com.collectionpack;

import java.util.ArrayList;

import java.util.Iterator;

/**

 * @author Abhinaw.Tripathi

 *

 */

public class ArrayListDemo {

/**

* @param args

*/

public static void main(String[] args) {

// TODO Auto-generated method stub

ArrayList<String> list=new  ArrayList<>();

list.add("Apple");

list.add("Mango");

list.add("Grapes");

list.add("Guava");

System.out.println("Contents= :" +list);

System.out.println("List size is :" +list.size());

System.out.println("Extracting from the list:");

Iterator it=list.iterator();

while(it.hasNext())

{

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

}

}

}

Output:

Contents= :[Apple, Mango, Grapes, Guava]

List size is :4

Extracting from the list:

Apple

Mango

Grapes

Guava