Is it necessary to overwrite the value in HashMap?

Question

Java

Yes HashMap<String, List<ArrayList<String>>, I get the value by key, add data to the ArrayList and leave it. Is this the right thing to do? Or can there be hidden consequences? Or is it better to change the entire old value to a new one using replace ?

Answer 1

Is that the right thing to do?

Yes, that's right, because The map only contains a link to the sheet. If you rewrite it, then you will just perform one useless action.