HashMap UUID or String as key?

Question

HashMap<UUID/String, Object>

Which is better? I know UUIDs dont use that much memory but what is generally better to use?

For *what* purpose? It's like asking what ball to use while not specifying the sport you're playing. — N.B., Jul 22 '14 at 12:47
Why *not* a string key (and what is the content)? Why *would* a UUID be better? — user2864740, Jul 22 '14 at 12:51

score 12 · Accepted Answer · answered Jul 22 '14 at 12:49

12

UUID takes up less space than the String does. Storing UUID itself via HashMap<UUID, MyObject> will conserve the space compared to HashMap<String, MyObject>.

answered Jul 22 '14 at 12:49

Rahul Tripathi

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what about sorting stuff – ntakouris Jul 22 '14 at 12:51
A UUID takes up less space than "hello world"? – user2864740 Jul 22 '14 at 12:52

score 6 · Answer 2 · edited Feb 08 '17 at 14:55

In general, the more specialized a type, the less waste there is, both regarding algorithms and storage.
Also, the data gets easier to manipulate.

Thus, if you know your argument is always a UUID, don't go for strings instead.

Ignoring that advice leads to a loosely typed mess, in extreme cases also known as stringly-typed-programs.

http://blog.codinghorror.com/new-programming-jargon
http://c2.com/cgi/wiki?StringlyTyped

cat with strings

HashMap UUID or String as key?

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