docker 1.6.2 stores auth information in ~/.dockercfg file in the following format:

{ "": {"auth": "", "email": "email@address.com"}}

but docker 1.8.1 stores it in ~/.docker/config.json in the following format:

{"auths": { "": {"auth": "", "email": "email@address.com"}}}

docker-java can't parse the latter form even when pointed at the file via DOCKER_CFG_PATH env variable, and so can't authenticate to secure remote repositories