HashMap ArrayList<Double[]>

public static void main(String[] args) {
        Hashtable ht = new Hashtable();

        //you add elements to Hashtable using put method
        //put(key, value)
        ht.put("Java", new Double[]{1.2, 2.4, 3.3});
        ht.put(".NET", new Double[]{1.2, 2.5, 5.6});
        ht.put("Javascript", new Double[]{1.2, 2.4, 3.1});
        ht.put("HTML", new Double[]{1.2, 2.4, 7.6});

        //looping through all the elements in hashtable
//        String str;
//        //you can retrieve all the keys in hashtable using .keys() method
//        Enumeration names = ht.keys();
//        while (names.hasMoreElements()) {
//            //next element retrieves the next element in the dictionary
//            str = (String) names.nextElement();
//            //.get(key) returns the value of the key stored in the hashtable
//            System.out.println(str + ": " + ht.get(str) + newLine);
//        }

        Set<String> keys = ht.keySet();
        for(String key: keys){
            System.out.println("key: "+key+"\nvalue: "+ht.get(key));
        }
    }