Two ways of traversing a map set

Import Java.util.HashMap;
Import Java.util.Iterator;
Import Java.util.Map;
Import Java.util.Set;

public class Maptest {public
	
	static void Main (string[] args) {
		
		HashMap map = new HashMap ();
		
		Map.put ("A", "John");
		Map.put ("B", "Dick");
		Map.put ("C", "Harry");
		Map.put ("A", "Zhao Liu");
		Map.put ("D", null);

		SYSTEM.OUT.PRINTLN ("---traversal way one---");
		
		Set set = Map.keyset ();	Returns the set of keys, which cannot be duplicated  because the contents of the set collection cannot be duplicated. For
		
		(Iterator iter = Set.iterator (); Iter.hasnext ();) {
			
			string key = (string) iter.next ();
			String value = (string) map.get (key);
			
			SYSTEM.OUT.PRINTLN (key + "----" + value);
		}
		
		
		SYSTEM.OUT.PRINTLN ("---traversal mode two---");
		
		Set Set2 = Map.entryset ();
		
		for (Iterator iter = Set2.iterator (); Iter.hasnext ();) {
		
			Map.entry Entry = (map.entry) iter.next ();
			
			String key = (string) entry.getkey ();
			String value = (string) entry.getvalue ();
			
			SYSTEM.OUT.PRINTLN (key + "---" + value);}}