Loading classes with many methods is very expensive

[Aleksey Shipilev]

Hi Martin,

On 23.10.2014 02:53, Martin Buchholz wrote:
> If you have a class with ~64k methods with a superclass that also has ~64k
> methods, class loading that single class will cost you ~30sec and calling
> Class.getMethods another ~10sec.  Both are unacceptably slow. I think both
> are due to O(N^2) algorithms, the first in hotspot, and the second in
> Class.java.

Interesting, this is the profile:
 http://cr.openjdk.java.net/~shade/8061949/calltree-1.txt

...and I submitted two issues as the result of this quick performance
investigation. We also need better benchmarks for this.
 https://bugs.openjdk.java.net/browse/JDK-8061949
 https://bugs.openjdk.java.net/browse/JDK-8061950

Nashorn also generates the mammoth classes on many cases, and therefore
solving both should (at least marginally) help there as well.

-Aleksey.