Question

I’m looking for a Java Map Class that can contains two or more keys for one value. It almost like MultiKeyMap in apache common collections, but it can use only one of the keys to retrieve the value instead of using all of keys.

For example to create an entry in the map for value “Hello World” with keys “key1” and “key2”:

    map.put("Hello World", "key1", "key2");

Then if I want to get the value, I can use two possible ways:

    String value = map.get("key1");

or

    String value = map.get("key2");

In MultiKeyMap, you need to specify all of the keys to retrive the value:

    String value = map.get("key1", "key2");

UPDATE:

People tell me to use regular Map class but I’m not sure if a map with two keys pointing to a same value will generate two duplicate values or not in memory. So anyone can confirm this?

Answer 1

Why not just repeat the Value for each Key in a regular map?