<p><em><strong>Update 2019-05-07</strong>: The java8 cask is affected by recent licensing changes by Oracle. There’s a <a href="https://github.com/Homebrew/homebrew-cask-versions/issues/7253">discussion over on github about this</a>. I’m leaving the post up partially for historic context, but the java8 cask is no longer available, at least at the time of writing.</em></p>

<p><em><strong>Update II - 2019-05-07</strong>: It looks like due to the recent licensing changes, the Java 8 JDK that brew used is not directly accessible anymore and likely behind some kind of paywall. The installation method described below will still work as it uses the non-versioned java cask, which installs the latest version of OpenJDK.</em></p>