Re: Collection

From:

Lew <lew@lewscanon.com>

Newsgroups:

comp.lang.java.programmer

Date:

Tue, 30 Oct 2007 20:42:30 -0400

Message-ID:

<QMKdna4QlJPrUrranZ2dnUVZ_rGrnZ2d@comcast.com>

Matt Humphrey wrote:

"Garg" <sendtogarg@gmail.com> wrote in message
news:1193671278.158017.3590@50g2000hsm.googlegroups.com...
| Thanks for your suggestions.
|

|
| but as Matt mentioned that the order deppends on the hashcode and
| order they are inserted(i think it only depends on the hashcode).

Just to clarify why the order of insertion matters, two distinct keys
("AAA", "QQQ") may produce the same hashcode and end up in the same bucket
list. In some cases you'll get AAA and then QQQ and in other cases you'll
get QQQ and then AAA, depending on how they were added to the list.

That's not all. For HashMap and other implementations, the order can change
during the life of the Map. When the Map grows to accommodate more entries,
it rearranges where things are in the structure.

<http://java.sun.com/javase/6/docs/api/java/util/HashMap.html>

This class makes no guarantees as to the order of the map;
in particular, it does not guarantee that the order will remain constant over time.

....

When the number of entries in the hash table exceeds
the product of the load factor and the current capacity,
the hash table is /rehashed/
(that is, internal data structures are rebuilt)
so that the hash table has approximately twice the number of buckets.

(emph. orig.)

--
Lew