import java.util.*;

public class CollectionTest {
	public static void main(String [] args) {   
		System.out.println( "Collection Example!\n" ); 
		int size;
		// Create a collection      
		HashSet <String>collection = new HashSet <String>();
		String str1 = "Yellow", str2 = "White", str3 = "Green", str4 = "Blue";  
		Iterator iterator;
		//Adding data in the collection
		collection.add(str1);    
		collection.add(str2);   
		collection.add(str3);   
		collection.add(str4);
		System.out.print("Collection data: ");  
		//Create a iterator
		iterator = collection.iterator();     
		while (iterator.hasNext()){
			System.out.print(iterator.next() + " ");  
		}
		System.out.println();
		// Get size of a collection
		size = collection.size();
		if (collection.isEmpty()){
			System.out.println("Collection is empty");
		}
		else{
			System.out.println( "Collection size: " + size);
		}
		System.out.println();
		// Remove specific data      
		collection.remove(str2);
		System.out.println("After removing [" + str2 + "]\n");
		System.out.print("Now collection data: ");
		iterator = collection.iterator();     
		while (iterator.hasNext()){
			System.out.print(iterator.next() + " ");  
		}
		System.out.println();
		size = collection.size();
		System.out.println("Collection size: " + size + "\n");
		//Collection empty
		collection.clear();
		size = collection.size();
		if (collection.isEmpty()){
			System.out.println("Collection is empty");
		}
		else{
			System.out.println( "Collection size: " + size);
		}
	}
}