Verification vs Validation

Shortest answer You can give for this:

Verification - do we build the thing right?

Validation - do we build the right thing?

Use Multiple Java Versions In OSX

Really common question today is - "How I can install and use several Java versions on my OSX without a headache?", so here's my answer.

Just follow simple and straightforward steps below (yes I did check those before publishing):

1. Check if You already have java installed:

$ java -version

2. If You have java locally then check location of installed version:

- installed from Apple - 

/System/Library/Java/JavaVirtualMachines/1.X.X.jdk/Contents/Home/

- installed from Oracle - 

/Library/Java/JavaVirtualMachines/jdk1.X.X_XX.jdk/Contents/Home

Remember that path.

3. Check if You have homebrew installed if not install it first:

- http://brew.sh/

4. Install jenv with homebrew:

$ brew install jenv

5. Add information about jenv into Your .bash_profile or .bashrc file:

if which jenv > /dev/null; then eval "$(jenv init -)"; fi

6. Save and reload .bashrc / .bash_profile:

$ source .bashrc (.bash_profile)

7. Check that jenv works properly:

$ jenv versions

This command should have next output by default:

$ * system (set by /Users/ajones/.jenv/version)

8. Add Your installed local java to jenv:

$ sudo jenv add /Library/Java/JavaVirtualMachines/jdkX.X.X_XX.jdk/Contents/Home/

Check if this added with jenv versions command.

9. Install cask with homebrew:

$ brew install cask

10. Install latest java from Oracle:

$ brew cask install java

Currently (March 2016) this command installs jdk1.8.0_74.jdk from Oracle.

11. Add latest installed java into jenv as peviously:

$ sudo jenv add /Library/Java/JavaVirtualMachines/jdkX.X.X_XX.jdk/Contents/Home/

12. Run jenv versions and verify that now You have 2 java versions installed on Your local machine

13. If You want to switch to needed version run:

$ sudo jenv local oracle64-1.7.X.XX or
$ sudo jenv local oracle64-1.8.X.XX

14. After each command You can run:

$ java -version

in order to check which java version is currently active.

15. If You want to change java version to all users:

$ sudo jenv global oracle64-1.7.X.XX or
$ sudo jenv global oracle64-1.8.X.XX


You can install as many java versions as You want - just add them to the jenv and then simply do switch when needed.