Sorting keys alphabetically in LinkedHashMap

Question

I have a LinkedHashMap and I want to sort its keys (which are Strings) alphabetically. However, it won't work with the Collections.sort() method, because it won't take either the LinkedHashMap itself nor the LinkedHashMap's keyset.

My only option is to sort them manually while filling the LinkedHashMap, but before doing that I wanted to know if anyone knows a better way.

What do you mean "sort the keys"? Do you want to *iterate* over the entries in alphabetical key order, or literally extract the keys and sort them? — Bohemian, Aug 17 '15 at 10:11
iterating over the entries alphabetically would be enough for me — ImNoProGrammer, Aug 17 '15 at 10:17

score 2 · Accepted Answer · answered Aug 17 '15 at 10:10

The better way is to use a Map which supports an order, like TreeMap.

However, if you have a broken design you can't fix you can do this.

 LinkedHashMap<String, String> map = ...
 TreeMap<String, String> copy = new TreeMap<>(map);
 map.clear();
 map.putAll(copy);

This will happen to work, but if you add a key, your map won't be sorted any more.

Sorting keys alphabetically in LinkedHashMap

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