Java equivalent of Perl's hash

Question

I\'ve been using a lot Perl hashes due to super flexibility and convenient. for instance, in Perl I can do the following:

$hash{AREA_CODE}->{PHONE}->{S         


        

Answer 1

Java has hashes, but because of strong typing they're not quite as flexible as hashes in Perl. Multidimensional hashes are harder to work with. In Perl, you can just declare a hash and let autovivification create the nested hashes on demand.

my %hash;
$hash{a}{b} = 1;

In Java, you have to declare it to be a hash-of-hashes up-front.

Map> hash = new HashMap>();
hash.put("a", new HashMap());
hash.get("a").put("b", new Integer(1));

For every extra dimension you need to add another nesting of Map to the declaration. Aside from being tedious, this isn't very OO.