Assuming you have installed Homebrew already, otherwise, you can go to the official website of homebrew and install it first, after that, use the following commands will help you install the latest Java (OpenJDK) in your Mac
1. Do the update first
brew update
2. Check the Java in Brew
At the time of installing, the latest stable version is 15.0.2
$ brew info java
openjdk: stable 15.0.2 (bottled) [keg-only]
Development kit for the Java programming language
https://openjdk.java.net/
Not installed
From: https://github.com/Homebrew/homebrew-core/blob/HEAD/Formula/openjdk.rb
License: Cannot Represent
3. Install Java
This will take a few minutes
brew install java
Sample Output
Updating Homebrew...
==> Auto-updated Homebrew!
Updated 1 tap (homebrew/core).
==> Updated Formulae
Updated 1 formula.
==> Downloading https://ghcr.io/v2/homebrew/core/openjdk/manifests/15.0.2
######################################################################## 100.0%
==> Downloading https://ghcr.io/v2/homebrew/core/openjdk/blobs/sha256:13e7d2b439
==> Downloading from https://pkg-containers.githubusercontent.com/ghcr1/blobs/sh
######################################################################## 100.0%
==> Pouring openjdk--15.0.2.big_sur.bottle.tar.gz
==> Caveats
For the system Java wrappers to find this JDK, symlink it with
sudo ln -sfn /usr/local/opt/openjdk/libexec/openjdk.jdk /Library/Java/JavaVirtualMachines/openjdk.jdk
openjdk is keg-only, which means it was not symlinked into /usr/local,
because macOS provides similar software and installing this software in
parallel can cause all kinds of trouble.
If you need to have openjdk first in your PATH, run:
echo 'export PATH="/usr/local/opt/openjdk/bin:$PATH"' >> ~/.profile
For compilers to find openjdk you may need to set:
export CPPFLAGS="-I/usr/local/opt/openjdk/include"
==> Summary
🍺 /usr/local/Cellar/openjdk/15.0.2: 614 files, 324.9MB
4. Create a Symbolic Link
Refer to the output message, it said openjdk is a keg-only, which means it was not symlinked into /usr/local, so we have do do this manually for us to run java command in the terminal
sudo ln -sfn /usr/local/opt/openjdk/libexec/openjdk.jdk /Library/Java/JavaVirtualMachines/openjdk.jdk
5. Verify it
java -version
You should see something like below
openjdk version "15.0.2" 2021-01-19
OpenJDK Runtime Environment (build 15.0.2+7)
OpenJDK 64-Bit Server VM (build 15.0.2+7, mixed mode, sharing)
seems like installing cask is not needed anymore in recent brew versions
Thanks, I have updated the post
very complicated