What is the best practice for KV object in java?

Question

What is the best practice for creating a single key value object in java? I know there is: Object, Pair, Map.Entry , KeyValue. For a simple KV use such as {"name":"coolName"} what should i use?

Answer 1

The most standard way to represent a key-value pair is with Map.Entry:

A map entry (key-value pair).

This is better than the others you suggest because:

• Object: has no notion of it having any meaningful structure
• Pair: better, but does not semantically convey that the first thing is a key and the second is a value.
• KeyValue: don't know what this is, but I don't think it's part of the standard SDK.

Map.Entry is in java.util, so it's available everywhere.

You can create an instance using:

new AbstractMap.SimpleEntry<>(key, value)

As pointed out by Michael, Java 9 adds a helper method:

Map.entry(key, value)

Answer 2

You can use Pair<K,V> (implementation of Map.Entry<K,V> from commons-lang3) and the relevant method in Java 11: Map.entry.