Revert "Merge pull request #6 from thewilli/java-bootstrap"

This reverts commit 5a8ee7c669556f5a776e96017c5d8967d86251fb, reversing
changes made to 39ca61eec8ec1090b3581d9eedced5189acfc5f8. The revert is required because it fails the build process. See http://hydra.nixos.org/build/9673476 for details.