Question

java list hashtable, arrayColection : what are the differences ?

Asked by: yarekGmail

Hello experts
I am new to java:

here are some types I found for collections:

Hashtable
HashMap
Collection
ArrayCollection
List
Map
Set

All seem very similar;
Can someone explain me what are they for and which one should I use ?

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Asked On
2009-11-08 at 09:22:35ID24881744
Tags

java

Topics

New to Java Programming

,

Java Programming Language

Participating Experts
4
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500
Comments
4

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Answers

 

by: CEHJPosted on 2009-11-08 at 09:46:32ID: 25771163

This will take you through the different collections and their uses:

http://java.sun.com/docs/books/tutorial/collections/index.html

 

by: javaexpertoPosted on 2009-11-08 at 10:44:15ID: 25771350

" List: An ordered collection of data items; i.e. you know exactly where each item is in the list.
A list can contain duplicate elements. ArrayList, LinkedList, and Vector are the classes that
implement the List interface.
" Map: An object that maps keys to values: each key can map to at most one value. Maps cannot
contain duplicate keys. HashMap and HashTable are examples of classes that implement the
Map interface. No duplicate keys are allowed in maps; duplicate values are allowed.
" Set: A collection of unique items; i.e. there are no duplicates. HashSet and LinkedHashSet are
examples of classes that implement the Set interface.

Collection is the super Interface of List and Set
ArrayCollection is not a class or interface in Java

Good luck

 

by: Thomas4019Posted on 2009-11-08 at 20:19:26ID: 25773360

As a new person to Java, 99% of the time you will use an ArrayList. All of the others are very useful, but you need some real experience before using them.


Also Map, HashMap and Hashtable and all about the same thing. To read about them read here.

http://java.sun.com/docs/books/tutorial/collections/interfaces/map.html

 

by: gurvinder372Posted on 2009-11-14 at 02:22:35ID: 25820090

20120131-EE-VQP-002

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