Is it possible to rename a Hashmap key?

I'm looking for a way to rename a Hashmap key, but i don't know if it's possible in Java.

Solution 1:

Try to remove the element and put it again with the new name. Assuming the keys in your map are String, it could be achieved that way:

Object obj = map.remove("oldKey");
map.put("newKey", obj);

Solution 2:

hashMap.put("New_Key", hashMap.remove("Old_Key"));

This will do what you want but, you will notice that the location of the key has changed.

Solution 3:

Assign the value of the key, which need to be renamed, to an new key. And remove the old key.

hashMap.put("New_Key", hashMap.get("Old_Key"));
hashMap.remove("Old_Key");

Solution 4:

You cannot rename/modify the hashmap key once added.

Only way is to delete/remove the key and insert with new key and value pair.

Reason : In hashmap internal implementation the Hashmap key modifier marked as final.

static class Entry<K ,V> implements Map.Entry<K ,V>
{
    final K key;
    V value;
    Entry<K ,V> next;
    final int hash;
    ...//More code goes here
}

For Reference : HashMap