Get error while cask, brew-cask

Question

I want install search engine elasticsearch in OS X 10.11.6

I read some blog

in my command line

brew install elasticsearch

and it show error(needs java)

elasticsearch: Java 1.7+ is required to install this formula.
You can install with Homebrew Cask:
  brew install Caskroom/cask/java

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

I flow this blog's solution

brew tap caskroom/cask

and show

Warning: Tap caskroom/cask already tapped.

second command

brew install brew-cask

it show error

Error: No available formula with the name "brew-cask"
==> Searching for similarly named formulae...
Error: No similarly named formulae found.
==> Searching taps...
This formula was found in a tap:
Caskroom/cask/brew-cask-completion
To install it, run:
  brew install Caskroom/cask/brew-cask-completion
==> You haven't updated Homebrew in a while.
A formula for brew-cask might have been added recently.
Run `brew update` to get the latest Homebrew updates!

and i install java

brew cask install java

but cask doesn't install

==> brew cask install Caskroom/cask/brew-cask-completion
Error: Unknown command: cask

and Some blog give me some advice

brew upgrade brew-cask

it show error

Error: No available formula with the name "brew-cask"

if fact I can't understand why my mac can't find cask...

please somebody helpme

Answer 1

Try this works for me.

I thought it's brew update install package command,

brew install --cask java

Answer 2

Problem Solved I need to brew update

brew update