List difference in java

Question

I have two ArrayList as follows:

original: 12, 16, 17, 19, 101

selected: 16, 19, 107, 108, 109

Answer 1

package LAB8Pack;
import java.util.HashSet; 
import java.util.Iterator;
import java.lang.StringBuilder; 


public class HashSetDemo {

    public static void main(String[] args) {
        HashSet round = new HashSet (); 
        HashSet green = new HashSet (); 


        // Add elements to 'round' and 'green' sets 
        //----------------------------------------------------
        round.add("peas"); 
        green.add("peas");
        round.add("watermelon"); 
        green.add("watermelon");
        round.add("basketball"); 
        green.add("chameleon");
        round.add("chameleon"); 
        green.add("grass");
        round.add("eyes"); 
        green.add("book");

        // Create 'setUnion' and 'setInter'  
        // ---------------------------------------------------
        HashSet setUnion = new HashSet();   

        // Use this to find the intersection
        HashSet SETINTER = new HashSet();   


        HashSet setInter1 = new HashSet(round);
        HashSet setInter2 = new HashSet(green);



        // Add all the elements to one set
        setUnion.addAll(round);
        setUnion.addAll(green);
        SETINTER.addAll(setUnion);



        // Create an intersection
        setInter1.removeAll(green); // Get unique items in round
        setInter2.removeAll(round); // Get unique items in green
        SETINTER.removeAll(setInter2); // Remove items that are unique to green
        SETINTER.removeAll(setInter1); // Remove items that are unique to round
        //----------------------------------------------------


        // DISPLAY RESULTS 
        // ===================================================
        System.out.println("Content of set round"); 
        System.out.println("-----------------------");
        System.out.println(OutputSet(round));

        System.out.println("Content of set green");
        System.out.println("-----------------------");
        System.out.println(OutputSet(green)); 

        System.out.println("Content of set Union");
        System.out.println("-----------------------");
        System.out.println(OutputSet(setUnion));



        System.out.println("Content of set Intersection"); 
        System.out.println("-----------------------");
        System.out.println(OutputSet(SETINTER));
    }




    // METHODS 
    // =======================================================
    static StringBuilder OutputSet (HashSet args) {
        Iterator iterator = args.iterator();
        StringBuilder sB = new StringBuilder (); 

        while (iterator.hasNext()) {
            sB.append(iterator.next() + " \n");
        }
        return sB; 
    }  
}