Java Installation on Mac
Internal
Overview
By default, no Javs is installed, when first attempting to use I get this:
NOMBP2:~ ovidiu$ java -version No Java runtime present, requesting install.
and a GUI window pops up: "to use the "java" command-line tool you need to install a JDK". More Info ... which says to go to the Oracle site.
Oracle SDK Installation
Download the latest for Mac (jdk-9.0.1_osx-x64_bin.dmg, jdk-8u25-macosx-x64.dmg or jdk-7u75-macosx-x64.dmg, depending of whether you need Java 9, Java 8 or Java 7).
Double-click on DMG, then on PKG.
By default, it will install it in /usr/bin/java, which is a link to /System/Library/Frameworks/JavaVM.framework/Versions/Current/Commands/java.
The default JAVA_HOME is:
/Library/Java/JavaVirtualMachines/jdk-9.0.1.jdk/Contents/Home/bin/java /Library/Java/JavaVirtualMachines/jdk1.8.0_25.jdk/Contents/Home
It can be obtained running
/usr/libexec/java_home
JAVA_HOME
For a standard installation the value of JAVA_HOME is returned by the result of /usr/libexec/java_home:
export JAVA_HOME=$(/usr/libexec/java_home)
...
export PATH=${JAVA_HOME}/bin:${PATH}
/usr/libexec/java_home returns returns the path to a Java home directory from the current user's settings.
In case multiple JDKs are installed, the java_home command line variables can be used to filter which JAVA_HOME is returned:
-v filters on version
-a filters on architecture
-d filters on data model.
To see al JVMs installed:
/usr/libexec/java_home -V
Using a Specific Java Installation when Multiple JDKs are Installed
Set in .bashrc (the following command selects Java 8 when Java 7, 8 and 9 are installed):
export JAVA_HOME=$(/usr/libexec/java_home -v 1.8)
export PATH=${JAVA_HOME}/bin:${PATH}
Default Java 1.6 Location
/Library/Java/Home/
If you want /usr/libexec/java_home to return the Java 6 home, run it with:
/usr/libexec/java_home -v 1.6