问题： mac安装java8sdk Cask ‘java8‘ is unavailable: ‘/usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask-versions/Casks/java8.rb‘ does not exist.
解决方案：
1、原因：brew cask install homebrew/cask-versions/java8
系统报错：Cask ‘java8‘ is unavailable: ‘/usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask-versions/Casks/java8.rb‘ does not exist.
2、方法：homebrew默认不支持java8，可以用
brew cask install homebrew/cask-versions/adoptopenjdk8Mac安装java8报错
原文：https://blog.51cto.com/siweilai/2536875
