What is the method for implementing an ordered hashmap?

In Java, HashMap is unordered, but if you want to implement an ordered Map, you can use LinkedHashMap. LinkedHashMap extends HashMap and uses a doubly linked list internally to maintain the insertion order or access order. By passing in the accessOrder parameter, you can decide whether to sort by insertion order or access order. For example, you can create an ordered Map sorted by insertion order using the following code:

Map<String, String> orderedMap = new LinkedHashMap<>(16, 0.75f, true);

The ‘accessOrder’ set to true means sorting based on access order, and set to false means sorting based on insertion order.