I know very little about binary java packages but there is gcj-overlay
that focuses on this. There is also wiki page.

http://overlays.gentoo.org/svn/proj/java/gcj-overlay/
http://overlays.gentoo.org/proj/java/wiki/GCJ_as_a_JDK

--
Miroslav Šulc



Rene Bartsch wrote:
> Hi,
>
> running Java bytecode in an VM is quite slow but compiling Java in
> host-optimized binaries would improve performance a lot.
>
> Because of that I want to propose a use-flag "java-binary" causing
> additional functions in the java eclasses to compile the ebuilds in
> host-optimized binary code.
>
> Have Phun with Gentoo
>
> Renne
>
>
>