On Unix

For illustrative purposes, assume that you have installed Java JDK at /opt/tools/jdk:

1. Open up a Terminal window.
2. Export JAVA_HOME=/opt/tools/jdk.
3. Export PATH=$PATH:$JAVA_HOME.

It is advisable to set this in your shell profile settings, such as .bash_profile
(for bash users) or .zshrc (for zsh users), so that you won't have to set it for each
new Terminal window you open.