How does one convert a HashMap to a List in Java?

Question

In Java, how does one get the values of a HashMap returned as a List?

Answer 1

Assuming you have:

HashMap map; // Assigned or populated somehow.

For a list of values:

List values = new ArrayList(map.values());

For a list of keys:

List keys = new ArrayList(map.keySet());

Note that the order of the keys and values will be unreliable with a HashMap; use a LinkedHashMap if you need to preserve one-to-one correspondence of key and value positions in their respective lists.