MapIsMultiMap

DRAFT

Correction

Here is what's right.

Wrong. A map contains only one value for a given key. If you call:

Map<String,String> map = ...
map.put("Hi", "value1");
map.put("Hi", "value2");

then the map will contain just one entry for key “Hi”: the last entry, (“Hi”, “value2”), you added for that key. That is, if you call map.get("Hi"), you will get back the value “value2”.

Note that this means that the keys in a map are a set. Each key exists just once in that map. You can get the set of keys by calling map.keySet():

Set<String> keys = map.keySet();