How to modify only the existing key of a hashmap but not its pair?

Question

HashMap<String,String> data = new HashMap<>();

data.put("AAA", "CCC");

I want to replace AAA with BBB during run-time without adding a new key into the map. Is this possible?

Answer 1

You can't*

There is no* way to edit existing key, the only way is to remove the old one and add a new key. The most elegant way to do it (IMHO) is this:

map.put( "newKey", map.remove( "oldKey" ) );

*: As @Michael Ziluck say in his comment and answer, you could technically do it with reflection, but as it destroy the integrity of HashTable, you should only do it at your own risk

Answer 2

Just delete old pair. Make a new pair with the new key and do insert.