How to set or change the default Java (JDK) version on OS X?

Question

How can you change the default version of Java on a mac?

Answer 1

If you are using fish and you are using mac and you want to be able to switch between JDK's, then below works for me on mac.

@kenglxn's answer didn't work for me and I figured out it bcos didn't set -g which is global !

Put below under ~/.config/fish/config.fish

alias j8="jhome  -v 1.8.0_162"
alias j9="jhome  -v 9.0.1"

function jhome
    set -g -x JAVA_HOME (/usr/libexec/java_home $argv)
    echo "JAVA_HOME:" $JAVA_HOME
    echo "java -version:"
    java -version
end

funcsave jhome

To know which version /minor version you have installed, you can do :

/usr/libexec/java_home -V                                                                              579ms  Wed 14 Feb 11:44:01 2018
Matching Java Virtual Machines (3):
    9.0.1, x86_64:  "Java SE 9.0.1" /Library/Java/JavaVirtualMachines/jdk-9.0.1.jdk/Contents/Home
    1.8.0_162, x86_64:  "Java SE 8" /Library/Java/JavaVirtualMachines/jdk1.8.0_162.jdk/Contents/Home
    1.8.0_121, x86_64:  "Java SE 8" /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home

Answer 2

Here is how I do it on my Linux (Ubuntu / Mint mate), I guess Mac can do it similarly.

---

Install & config

Steps:

• [Basic - part]
• Download jdk (the .tgz file) by hand.
• Uncompress & rename properly, at a proper location.
  e.g /mnt/star/program/java/jdk-1.8
• Make a soft link, which will be changed to switch java version later.
  e.g ln -s /mnt/star/program/java/jdk-1.8 /mnt/star/program/java/java
  Thus /mnt/star/program/java/java is the soft link.
• Set JAVA_HOME in a start script.
  Could use file like /etc/profile.d/eric.sh, or just use ~/.bashrc.
  e.g JAVA_HOME=/mnt/star/program/java/java
• Then open a new bash shell. java -version should print the java version.
• [More version - part]
• Download & install more Java version, as need, similar as above steps.
  e.g
  /mnt/star/program/java/jdk-11
• [Switch - part]
• In ~/.bashrc, define variable for various Java version.
  e.g
  _E_JAVA_HOME_11='/mnt/star/program/java/jdk-11'
_E_JAVA_HOME_8='/mnt/star/program/java/jdk-8'
# dir of default version,
_E_JAVA_HOME_D=$_E_JAVA_HOME_8
• In ~/.bashrc, define command to switch Java version.
  e.g
  ## switch java version,
alias jv11="rm $JAVA_HOME; ln -s $_E_JAVA_HOME_11 $JAVA_HOME"
alias jv8="rm $JAVA_HOME; ln -s $_E_JAVA_HOME_8 $JAVA_HOME"
# default java version,
alias jvd="rm $JAVA_HOME; ln -s $_E_JAVA_HOME_D $JAVA_HOME"
alias jv="java -version"
• In terminal, source ~/.bashrc to make the changes take effect.
• Then could switch using the defined commands.

---

Commands - from above config

Commands:

• jv11
  Switch to Java 11
• jv8
  Switch to Java 8
• jvd
  Switch to default Java version, which is denoted by _E_JAVA_HOME_D defined above.
• jv
  Show java version.

Example output:

eric@eric-pc:~$ jv
java version "1.8.0_191"
Java(TM) SE Runtime Environment (build 1.8.0_191-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.191-b12, mixed mode)

eric@eric-pc:~$ jv11
eric@eric-pc:~$ jv
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)

eric@eric-pc:~$ jvd
eric@eric-pc:~$ jv
java version "1.8.0_191"
Java(TM) SE Runtime Environment (build 1.8.0_191-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.191-b12, mixed mode)

eric@eric-pc:~$ 

---

Mechanism

• It switch by changing the soft link, which is used as JAVA_HOME.

---

Tips

• On my machine when install jdk by hand, I keep the minor version, then make a soft link with the major version but without the minor version.
  e.g
  // this is the actual dir,
  jdk1.8.0_191

  // this is a soft link to jdk1.8.0_191
jdk-8

  // this is a soft link to jdk-8 or jdk-11
java

• I define command alias in ~/.bashrc, but define variable in a separate file.
  I am using ~/.eric_var to define the variables, and ~/.bashrc will source it (e.g source $HOME/.eric_var).

Answer 3

It is a little bit tricky, but try to follow the steps described in Installing Java on OS X 10.9 (Mavericks). Basically, you gonna have to update your alias to java.

Step by step:

After installing JDK 1.7, you will need to do the sudo ln -snf in order to change the link to current java. To do so, open Terminal and issue the command:

sudo ln -nsf /Library/Java/JavaVirtualMachines/jdk1.7.0_51.jdk/Contents \
/System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK

Note that the directory jdk1.7.0_51.jdk may change depending on the SDK version you have installed.

Now, you need to set JAVA_HOME to point to where jdk_1.7.0_xx.jdk was installed. Open again the Terminal and type:

export JAVA_HOME="/Library/Java/JavaVirtualMachines/jdk1.7.0_51.jdk/Contents/Home"

You can add the export JAVA_HOME line above in your .bashrc file to have java permanently in your Terminal

Answer 4

An easy way to include a separately installed JDK in the list given by /usr/libexec/java_home -V is to symlink the directory as follows:

sudo ln -s path/to/jdk /Library/Java/JavaVirtualMachines/jdk-[some-identifier].jdk

For example, to register the JDK included with Android Studio (1.8.0_152 at the time of writing), use:

sudo ln -s /Applications/Android\ Studio.app/Contents/jre/jdk /Library/Java/JavaVirtualMachines/jdk-android-studio.jdk

Now java_home will list the JDK under Matching Java Virtual Machines and you can select it as described above.

Answer 5

install JDK, not just JRE

/usr/libexec/java_home -v 1.8

gives

/Library/Java/JavaVirtualMachines/jdk1.8.0_111.jdk/Contents/Home

next

touch .bash_profile

open -a TextEdit.app .bash_profile

TextEdit will show you a blank page which you can fill in.

add to doc: export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_111.jdk/Contents/Home

in terminal:

export JAVA_HOME="$(/usr/libexec/java_home -v 1.8)"

try the command:

javac -version

should output:

javac 1.8.0_111

Answer 6

Use jenv, it is like a Java environment manager. It is super easy to use and clean

For Mac, follow the steps:

brew install jenv

git clone https://github.com/gcuisinier/jenv.git ~/.jenv

Installation: If you are using bash follow these steps:

$ echo 'export PATH="$HOME/.jenv/bin:$PATH"' >> ~/.bash_profile

echo 'eval "$(jenv init -)"' >> ~/.bash_profile

$ exec $SHELL -l

Add desired versions of JVM to jenv:

jenv add /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home

jenv add /System/Library/Java/JavaVirtualMachines/1.8.0.jdk/Contents/Home

Check the installed versions:

jenv versions

Set the Java version you want to use by:

jenv global oracle64-1.6.0