PostgreSQL port to pure Java?

Has this subject been discussed before?
I did not find any references to it in the archives.

I think that a co-bundle between an open source J2EE
container like JBoss and a scalable database like
PostgreSQL will be a blast.

There are several well performing comercial Java dbs
out there and there is Hypersonic which is free and
fast, but supports only READ_UNCOMMITED and is build
to grow up to ~200MB.

Ivelin