What collection should I choose?

I need just a collection of two pairs of data, none of them is going to be null. I don't need any sorting or other possibilities. What implementation of M开发者_高级运维ap should I choose?

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Map Implementations:

The three general-purpose Map implementations are HashMap, TreeMap and LinkedHashMap. If you need SortedMap operations or key-ordered Collection-view iteration, use TreeMap; if you want maximum speed and don't care about iteration order, use HashMap; if you want near-HashMap performance and insertion-order iteration, use LinkedHashMap. In this respect, the situation for Map is analogous to Set. Likewise, everything else in the Set Implementations section also applies to Map implementations

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HashMap is usually the default choice. It gives one O(1) lookup.

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HashMap is most commonly used for such Key-Value pairs.