Set DataStructure

[Anony!]

Hi

I know that a list contains duplicates and a set does not.

Whats the difference between the 3 implementations of the set interface?
They being the hashset, linkedhashset, and treeset?

What I predict:

1. Hashset: dont know.
2. LinkedHashSet: no order, elements in a linkedlist structure, and has no
duplicates.
3. Treeset: orders elements in a tree-like structure and has no duplicates.

Anyone want to complete the picture?

Thanks.
AaA

 

[Murray]

1. Hashset: dont know.

HashSet has no guaranteed order. Order may even change over time. It is
based on the hashCode of an object (which is essentially random) and it is
backed by a HashMap implementation

LinkedHashSet has a predictable order i.e. insertion order

TreeSet uses natural ordering of Comparable elements, or a supplied
Comparator

By the way, all this info is easily found in the Java API e.g.
http://java.sun.com/j2se/1.4.2/docs/api/ or you own local copy

 

[Anony!]

HashSet has no guaranteed order. Order may even change over time. It is
based on the hashCode of an object (which is essentially random) and it is
backed by a HashMap implementation

I thought a hashcode for an object is unique to that object and would not
change.