Check out example codes for "how to add java_home in mac". It will help you in understanding the concepts better.

Code Example 1

1. Open terminal window
2. Type command: $ vim ~/.bash_profile and Hit Enter
3. Type command: $ export JAVA_HOME=$(/usr/libexec/java_home) and press Escape key for Save changes.
4. Type command: :(colon)wq, It will Save and close .bash_profile file.
5. Type command: source ~/.bash_profile and hit Enter
6. Now we can check the value of the JAVA_HOME variable:
7. Type Command: echo $JAVA_HOME
 The result should be the path to the JDK installation:

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