Java OCA OCP Practice Question 2963

2. import java.util.*;  
3. public class Main {  
4.   public static void main(String[] args) {      
5.     Set s1 = new HashSet();  
6.     s1.add(0);  /*from   w w w  . ja  v a2s .com*/
7.     s1.add("1");  
8.     doShape(s1);  
9.   }   
10.   static void doShape(Set<Number> s) {  
11.     do2(s);  
12.     Iterator i = s.iterator();  
13.     while(i.hasNext())  System.out.print(i.next() + " ");  
14.     Object[] oa = s.toArray();  
15.     for(int x = 0; x < oa.length; x++)  
16.       System.out.print(oa[x] + " ");  
17.     System.out.println(s.contains(1));  
18.   }  
19.   static void do2(Set s2) { System.out.print(s2.size() + " "); }      
20. }