MacでEmacs用にJAVA_HOME設定した

たぶん他にもいい方法はありそうだが

;; JAVA_HOME
(setenv "JAVA_HOME" (replace-regexp-in-string "\n$" "" (shell-command-to-string  "/usr/libexec/java_home -v 1.7")))

Emacs: Set Environment Variables within Emacs

qiita.com

stackoverflow.com