Or try this (fairly recent) version of OpenJDK that I have repackaged from Fedora to Centos 5, it contains the browser plugin (i386 much less tested than x86_64): http://www.argeo.org/linux/argeo-el/5/plus/i386/
So there is, once again, an openjdk browser plugin? There hasn't been for a while.
The i386 and x86_64 plugins are different codebase, and as I said, i386 has been much less tested. Feedback welcome.