使用插入顺序作为顺序实现java.util.Map

Question

The JDK documentation on java.util.Map states

The order of a map is defined as the order in which the iterators on the map's collection views return their elements. Some map implementations, like the TreeMap class, make specific guarantees as to their order; others, like the HashMap class, do not.

And the documentation on TreeMap states:

The map is sorted according to the natural ordering of its keys, or by a Comparator provided at map creation time, depending on which constructor is used.

Is there any JDK implementation of Map that uses the order that elements were inserted into the map as the order?

Answer 1

java.util.LinkedHashMap :

This implementation differs from HashMap in that it maintains a doubly-linked list running through all of its entries. This linked list defines the iteration ordering, which is normally the order in which keys were inserted into the map ( insertion-order ). Note that insertion order is not affected if a key is re-inserted into the map.