I don't know, but it's much slower than I expected.
It's the latest Java installable by apt on Debian (all these tests are run in Debian running under VMWare).<p><pre><code>  $ java -version
  java version "1.6.0_0"
  OpenJDK  Runtime Environment (build 1.6.0_0-b11)
  OpenJDK 64-Bit Server VM (build 1.6.0_0-b11, mixed mode)</code></pre>