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Editorial Team
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Asked: 2026-05-18T12:38:13+00:00

Which is the best way to compute the hash code of a Map ,

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Which is the best way to compute the hash code of a Map, knowing that it may contain entry values of types such as: String, Integer, Object[] … ?

Map.hashCode() returns a shallow hash code. That means that if you have a String[] in your map, the Map.hashCode() will also use the hash returned by the String[]. Which, unfortunately, is not what I want (the Object.hashCode() implementation). But I want the Arrays.hashCode(String[]) implementation.

So which is the best, generic, approach to handle this ?

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1 Answer

  1. Editorial Team

    If you need to know if two maps contain the same values, you will need to write a deep comparison method. you shouldn’t be depending on hashCode.

    even with a perfect algorithm, there’s no way that every possible collection of every possible object could be uniquely represented by a single signed integer.

    Hashcode is just for collision reduction when used in collections, it is not supposed to be used to uniquely identify objects.

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