Can HashMap accepts null value as key in Java

In Java, a HashMap allows one null key. You cannot store multiple null keys because keys must be unique. However, a HashMap can store multiple null values, as values are not required to be unique.

Example:

HashMap<Integer, Integer> map = new HashMap<>();
map.put(null, 1); // Storing a null key
map.put(2, null); // Storing a null value
map.put(3, null); // Multiple null values are allowed