import java.util.Iterator;
import java.util.Set;
import java.util.TreeSet;

public class ConcurrentSkipListMapTest {
public static void main (String args)
{
Set set = new TreeSet();
set.add(1);
set.add(“2”);
set.add(3);

Iterator iterator = set.iterator();
while (iterator. hasNext())
{
System. out. print(iterator. next()+””);
}
}

}