18-03-25
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Q)Example program on methods of Collection interface.
//CollectionInterfaceExample.java
import java.util.*;
class CollectionInterfaceExample{

	public static Collection<Integer> getCollection(){
         return new ArrayList<Integer>();//list based collection object created and returned
	}//user defined method

	public static void main(String[] args){
		Collection<Integer> collection1=getCollection();//step 1:- creating collection object
		System.out.println(collection1.getClass().getName()+" class object created");
		collection1.add(10);
		collection1.add(13);
		collection1.add(14);
		collection1.add(15);//step 2:- add elements to the collection
		System.out.println(collection1);
		Collection<Integer> collection2=getCollection();
		collection2.addAll(collection1);
                System.out.println(collection2);
		System.out.println("Is 14 present in collection 1:"+collection1.contains(14));
		System.out.println("No of elements in collection 2:"+collection2.size());
		collection2.clear();
                System.out.println("No of elements in collection 2:"+collection2.size());
		for(int element:collection1){
              System.out.println(element);
		}//1 way of iterating over a collection
		Iterator i=collection1.iterator();//cursor object returned.
		while(i.hasNext()){
			System.out.println(i.next());
		}//2nd way of iterating a collection
		System.out.println(" Is 13 removed from the collection :"+collection1.remove(13));
		System.out.println(collection1);
		collection1.clear();
		Collections.addAll(collection1,10,11,12);
		Collections.addAll(collection2,11,12);
		collection1.removeAll(collection2);
		System.out.println(collection1);
	}
}
Q)Explain about a list based collection.
=>A collection object that implements java.util.List interface is nothing but a list
based collection.

=>A list based collection is also known as an ordered or indexed collection.

=>In a list based collection; insertion order is preserved,duplicate elements are allowed
and nulls can be inserted.