What are the pros and cons of LinkedHashMaps vs. LinkedHashSets?

Question

I was just wondering if someone could espouse for me the main benefits for choosing one over the other and the detriments that come with that choice.

Answer 1

One's a set, and one's a map. Choose the correct data structure for a given scenario.

Answer 2

A Set has just values, you cannot put duplicates in. a Map has a key/value pair. They have different uses.

A set will get used as a collection, passing in a group of objects, whereas a map is useful for when you have a unique key to identify each element and you want to be able to access it by that key.

Answer 3

They solve different problems, LinkedHashMap does a mapping of keys to values, a LinkedHashSet simply stores a collection of things with no duplicates.

A linked hash map is for mapping key/value pairs -- for example, storing names and ages:

Map<String,Integer> namesAndAges = new LinkedHashMap<String,Integer>();
namesAndAges.put("Benson", 25);
namesAndAges.put("Fred", 19);

On the other hand, a linked hash set is for storing a collection of one thing -- names, for example:

Set<String> names = new LinkedHashSet<String>();
names.add("Benson");
names.add("Fred");

Answer 4

LinkedHashMap and LinkedHashSet has only one difference and that comes by HashMap and HashSet difference, their parents. Again, HashSet is just a variation of HashMap. You can say HashSet as a HashMap with all values pointing to a single final object. Therefore, both of them does not give you much differences.

Using LinkedHashSet, You shall be using only one final object other than your keys. Using LinkedHashMap, if you set values as null for all keys, then its better than LinkedHashSet for Set purpose as well.