개발새발 IT

import java.util.HashMap;

import java.util.Hashtable;

import java.util.Set;

public class dailyCode {

public static void main(String[] args) {

Hashtable<String, String> ht = new Hashtable<String, String>();

ht.put("name", "Alex");

ht.put("age", "21");

//ht.put("age", null); Hashtable can't have null value.

HashMap<String, String> hm = new HashMap<String, String>();

hm.put("name", null);

hm.put("age", null); //HashMap can have null value.

hm.put("name", "James");

Set<String> keys = ht.keySet();

for(String key : keys) {

System.out.println(key + " = " + ht.get(key));

}

keys = hm.keySet();

for(String key : keys) {

System.out.println(key + " = " + hm.get(key));

}

}

}