import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

public class Test {
    public static void main(String[] args) {
         Map userMap=new HashMap();
         userMap.put("Tom", "boy");
         userMap.put("Mary", "girl");

         String sex=(String) userMap.get("Tom");
         System.out.println(sex);


         Iterator iter=userMap.keySet().iterator();
         while(iter.hasNext()){
             Object key=iter.next();
             Object val=userMap.get(key);

             System.out.println((String)key);
             System.out.println((String)val);
         }
    }

}