❯ brew install maven
[16:27:20]
maven: Java 1.7+ is required to install this formula.
JavaRequirement unsatisfied!

You can install with Homebrew-Cask:
  brew cask install java

You can download from:
https://www.oracle.com/technetwork/java/javase/downloads/index.html
Error: An unsatisfied requirement failed this build.

❯ brew config                                                       [16:30:37]
HOMEBREW_VERSION: 1.3.5-28-gc4e8c79
ORIGIN: https://github.com/Homebrew/brew
HEAD: c4e8c7906d12399b34188cd3395b8f9d30dc89b3
Last commit: 75 minutes ago
Core tap ORIGIN: https://github.com/Homebrew/homebrew-core
Core tap HEAD: ebaf0a5b91c45b9ff3b99dfc5b7955a420cafb5f
Core tap last commit: 8 minutes ago
HOMEBREW_PREFIX: /usr/local
HOMEBREW_REPOSITORY: /usr/local/Homebrew
HOMEBREW_CELLAR: /usr/local/Cellar
HOMEBREW_BOTTLE_DOMAIN: https://homebrew.bintray.com
CPU: octa-core 64-bit skylake
Homebrew Ruby: 2.3.3 => /usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/2.3.3/bin/ruby
Clang: 9.0 build 900
Git: 2.14.2 => /usr/local/bin/git
Perl: /usr/bin/perl
Python: /usr/bin/python
Ruby: /usr/bin/ruby => /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby
Java: 9.0.1
macOS: 10.12.6-x86_64
Xcode: N/A
CLT: 9.0.1.0.1.1506734476
X11: N/A