import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;
public class Main {
public static void main(String[] args) {
HashMap hMap = new HashMap();
hMap.put("1", "One");
hMap.put("2", "Two");
hMap.put("3", "Three");
Set st = hMap.keySet();
Iterator itr = st.iterator();
while (itr.hasNext())
System.out.println(itr.next());
// remove 2 from Set
st.remove("2");
System.out.println(hMap.containsKey("2"));
}
}