Where is JAVA_HOME on macOS Mojave (10.14) to Lion (10.7)?

Update for Java 9 and some neat aliases.

In .bash_profile:

export JAVA_HOME8=`/usr/libexec/java_home --version 1.8`
export JAVA_HOME9=`/usr/libexec/java_home --version 9`

Note, that for the latest version it is 9 and not 1.9.

Set active Java:

export JAVA_HOME=$JAVA_HOME8
export PATH=$JAVA_HOME/bin:$PATH

Some additional alias to switch between the different versions:

alias j8='export JAVA_HOME=$JAVA_HOME8; export PATH=$JAVA_HOME/bin:$PATH'
alias j9='export JAVA_HOME=$JAVA_HOME9; export PATH=$JAVA_HOME/bin:$PATH'

Test in terminal:

% j8
% java -version
java version "1.8.0_121"
Java(TM) SE Runtime Environment (build 1.8.0_121-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.121-b13, mixed mode)
% j9
% java -version
java version "9"
Java(TM) SE Runtime Environment (build 9+181)
Java HotSpot(TM) 64-Bit Server VM (build 9+181, mixed mode)

EDIT: Update for Java 10

export JAVA_HOME10=`/usr/libexec/java_home --version 10`
alias j10='export JAVA_HOME=$JAVA_HOME10; export PATH=$JAVA_HOME/bin:$PATH'

EDIT: Update for Java 11

export JAVA_HOME11=`/usr/libexec/java_home --version 11`
alias j11='export JAVA_HOME=$JAVA_HOME11; export PATH=$JAVA_HOME/bin:$PATH'

for macOS Mojave 10.14.1 and JAVA 11.0.1 I set the profile as

export JAVA_HOME=$(/usr/libexec/java_home)

key in terminal this to confirm:

$JAVA_HOME/bin/java -version

java version "11.0.1" 2018-10-16 LTS
Java(TM) SE Runtime Environment 18.9 (build 11.0.1+13-LTS)
Java HotSpot(TM) 64-Bit Server VM 18.9 (build 11.0.1+13-LTS, mixed mode)

I Had to explicitly set it to the exact path on my Macbook air .

Steps followed:

1. try to echo $JAVA_HOME (if it's set it'll show the path), if not, try to search for it using sudo find /usr/ -name *jdk
2. Edit the Bash p with - sudo nano ~/.bash_profile
3. Add the exact path to JAVA Home (with the path from step 2 above) export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home
4. Save and exit
5. Check JAVA_Home using - echo $JAVA_HOME

I am running MACOS MOJAVE - 10.14.2 (18C54) on a Macbook Air with JAVA 8

For Fish terminal users on Mac (I believe it's available on Linux as well), this should work:

set -Ux JAVA_8 (/usr/libexec/java_home --version 1.8)
set -Ux JAVA_12 (/usr/libexec/java_home --version 12)
set -Ux JAVA_HOME $JAVA_8       //or whichever version you want as default

For Java 11 (JDK 11) it can be located with the following command:

/usr/libexec/java_home -v 11

I'm using Fish shell on High Sierra 10.13.4 and installed Java via Brew.

It's not automatically set up so to set it correctly on my system I run:

set -U JAVA_HOME (/usr/libexec/java_home)

Just set java_home of 1.8 jdk version in netbeans.conf file:

/Applications/NetBeans/NetBeans 8.2.app/Contents/Resources/NetBeans/etc/netbeans.conf

uncomment line:

netbeans_jdkhome="path/to/jdk"

and set path to your 1.8 jdk, in my case:

netbeans_jdkhome="/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home"

This approach lays you to have several jdk versions on mac os

Handy command for knowing java home and other details.

java -XshowSettings:properties -version

and to know all java homes on your mac:

/usr/libexec/java_home -V