Java Collections

ArrayList in java collections 

ArrayList is a class which implements List interface. It is widely used because of the functionality and flexibility it offers. Most of the developers choose Arraylist over Array as it’s a very good alternative of traditional java arrays.

- ArrayList stores the element’s value alone and internally maintains the indexes for each element.
- ArrayList maintains the insertion order while HashMap doesn’t. Which means ArrayList returns the list items in the same order in which they got inserted into the list.
- ArrayList allows duplicate elements 
- ArrayList can have any number of null elements.
- ArrayList  get the element by specifying the index of it. 

Example Below : 

import java.util.ArrayList;

public class Details {
public static void main(String args[]) {
  ArrayList<String> arrStr = new ArrayList<String>();
  arrStr.add("Item1");
  arrStr.add("Item2");
  arrStr.add("Item6");
  arrStr.add("Item9");
  arrStr.add("Item8");
  arrStr.add("Item7");
  arrStr.add("Item3");
  arrStr.add("Item4");
   System.out.println("Item in array list are: "+arrStr);
  }

}
you will see the result like this : 
Item in array list are: [Item1, Item2, Item6, Item9, Item8, Item7, Item3, Item4]