Writing a Map implementation is a bit more difficult than some other collection interfaces. The task would be made easier if some assistance were provided in writing the Map.Entry implementation that all Map implementations must provide.

It would make sense for java.util to provide a "basic map entry" that was simply a container for a key and a value that knew how to compute the proper equals, hashCode and toString functions.

In fact, such a class already exists privately inside AbstractMap with the notation "This should be made public as soon as possible."