import java.util.HashMap; import java.util.Iterator; import java.util.Set; public class Main { public static void main(String[] args) { HashMap<String, String> hMap = new HashMap<String, String>(); 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")); } }