j, jco, jc or jo don't exist after installing autojump on Mac OSX Yosemite

If you haven't done so already, you may want to follow the instructions printed on my most recent install:

Add the following line to your ~/.bash_profile or ~/.zshrc file (and remember
to source the file to update your current session):
  [[ -s $(brew --prefix)/etc/profile.d/autojump.sh ]] && . $(brew --prefix)/etc/profile.d/autojump.sh

For example, if you added the line to .bash_profile, you can source it as follows:

. ~/.bash_profile

Or, just spin up a new command shell and the variables should have taken effect.

If you don't have any success with that, it's time to seriously trouble-shoot.

If you installed correctly, you should have a file named autojump.sh under your brew directory (which you can see using brew --prefix). If that file's there, you should be able to perform the following command, which should temporarily allow use of autojump commands in that particular shell:

. $(brew --prefix)/etc/profile.d/autojump.sh 

If you are successful with the autojump commands, it's a matter of modifying your .bashrc or .zshrc file as stated at the top of this answer.

If autojump commands are still nowhere in sight, I'd try a "brew uninstall autojump" followed by a "brew install autojump". Oh, and be sure to follow precisely the instructions in the "Caveats" section following the successful install.

Assumed that you use zsh shell, you have to manually add the plugin link. See the instructions blew:

1. open .zshrc file

   nano ~/.zshrc or vim ~/.zshrc

2. add plugins=(autojump) in the file

3. re-open your terminal