e356. creating a map that retains order-of-insertion.txt

这里面包含了一百多个JAVA源文件

Map map = new LinkedHashMap();
    
    // Add some elements
    map.put("1", "value1");
    map.put("2", "value2");
    map.put("3", "value3");
    map.put("2", "value4");
    
    // List the entries
    for (Iterator it=map.keySet().iterator(); it.hasNext(); ) {
        Object key = it.next();
        Object value = map.get(key);
    }
    // [1=value1, 2=value4, 3=value3]