Portage receives a 404 response when attempting to download openjdk-6-src-b29-05_dec_2013.tar.gz for icedtea-6.9999. I fixed it by changing the first SRC_URI to: http://java.net/projects/openjdk6/downloads/download/${OPENJDK_TARBALL} Reproducible: Always
I can confirm that the current SRC_URI for icedtea-6.9999 is correct.