Generic Collection

Generic collection allows you to have only one type of items in collection.Advantage is that typecasting is not required at run time.

Non generic way of creating a collection:

ArrayList list1=new ArrayList();

New generic declaration
ArrayList<String> list1=new ArrayList<String>();

Example:

import java.util.ArrayList;
import java.util.Iterator;

public class GenericArrayList
{

public static void main(String[] args)
{
ArrayList<String> list1=new ArrayList<String>();
       
  list1.add("Ravi");//adding object in arraylist
  list1.add("Vijay");
  list1.add("Ravi");
  list1.add("Ajay");
 //list1.add(new Integer(10));
    //uncommenting the above will give error.

 //Iterating the elements of Collection by using Iterator interface
 Iterator itr=list1.iterator();
 while(itr.hasNext())
 {
 System.out.println(itr.next());
 }
   

 //Iterating the elements of Collection by for-each loop
 for(String obj:list1)
  {
  System.out.println(obj);
  }

}

}