[zrail]

This has been true for quite a long time, and IIRC is why they're not more widely used. That and they're pretty complicated to implement properly.

[beagle3]

They are only better for some workloads and not others. e.g., they are excellent for accessing data in-order, but are worse than a very simple hash table for random access:

http://preshing.com/20130107/this-hash-table-is-faster-than-...

(yes, this hash table is vulnerable to timing attacks; point is, for many workloads Judy brings in considerable complexity but is actually inferior to other solutions).

[snogglethorpe]

Just an aside, but man, that's a refreshingly readable and pleasant article...

[lsb]

That, and because they need to be tuned for each individual cache line size.

See http://nothings.org/computer/judy/ for a more thorough analysis of Judy arrays (at 20 kLoC) versus straightforward hash tables (at 0.2 kLoC).