Website : http://www.jenv.be
Maintainers :
Future maintainer in discussion:
As he makes an incredible work by taking time to merge the Pull Request on his fork, I (@gcuisinier) am in discussion with him to take part of jEnv directly if he wants. Whatever his decision, I thank him for his work, and to have convincing me to think about the future of jEnv and accepting a new maintainer for the good of the project.
This is an updated fork of jenv
, a beloved Java environment manager adapted from rbenv
.
jenv
gives you a few critical affordances for using java
on development machines:
- It lets you switch between
java
versions. This is useful when developing Android applications, which generally require Java 8 for its tools, versus server applications, which use later versions like Java 11. - It sets
JAVA_HOME
inside your shell, in a way that can be set globally, local to the current working directory or per shell.
However, this project does not:
- Install
java
for you. Use your platform appropriate package manager to installjava
. On macOS,brew
is recommended.
This document will show you how to install jenv
, review its most common commands, show example workflows and identify known issues.
Follow the steps below to get a working jenv
installation with knowledge of your java
environment. Read all the code you execute carefully: a $
symbol at the beginning of a line should be omitted, since it's meant to show you entering a command into your terminal and observing the response after the command.
On macOS, you can install jEnv using Homebrew:
brew install jenv
Or if you use MacPorts on macOS:
sudo port install jenv
Alternatively, and on Linux, you can install it from source:
git clone https://github.com/jenv/jenv.git ~/.jenv
jEnv needs to be intialised in your shell by evalling the output of jenv init -
. e.g.
# Shell: bash
echo 'export PATH="$HOME/.jenv/bin:$PATH"' >> ~/.bash_profile
echo 'eval "$(jenv init -)"' >> ~/.bash_profile
# Shell: zsh
echo 'export PATH="$HOME/.jenv/bin:$PATH"' >> ~/.zshrc
echo 'eval "$(jenv init -)"' >> ~/.zshrc
To have JAVA_HOME
get set by jEnv, enable the export
plugin. This needs to be done in an initialised shell:
eval "$(jenv init -)"
jenv enable-plugin export
Restart your shell by closing and reopening your terminal window or running exec $SHELL -l
in the current session for the changes to take effect.
exec $SHELL -l
To verify jenv
was installed and initialised, run jenv doctor
. On a macOS machine, you'll observe the following output:
$ jenv doctor
[OK] No JAVA_HOME set
[ERROR] Java binary in path is not in the jenv shims.
[ERROR] Please check your path, or try using `jenv add /path/to/java/home`
PATH : /Users/user/.jenv/libexec:/Users/user/.jenv/shims:/Users/user/.jenv/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin
[OK] Jenv is correctly loaded
Observe that jenv
is correctly loaded but Java is not yet installed. To rememedy this, see "Adding Your Java Environment" below.
Problem? Please visit the Trouble Shooting Wiki page.
Untested: While this fork has improved fish
shell support, it has not been tested by this maintainer. To install jenv
for Fish according to the contributor's instructions:
echo 'set PATH $HOME/.jenv/bin $PATH' >> ~/.config/fish/config.fish
echo 'status --is-interactive; and jenv init - | source' >> ~/.config/fish/config.fish
cp ~/.jenv/fish/jenv.fish ~/.config/fish/functions/jenv.fish
Use jenv add
to inform jenv
where your Java environment is located. jenv
does not, by itself, install Java.
For example, on macOS, use brew
to install the latest Java (OpenJDK 21, also follow the caveat steps to symlink into the system virtual machines) followed by the appropriate jenv add PATH_TO_JVM_HOME
command to recognize it.
brew install java
sudo ln -sfn /usr/local/opt/openjdk/libexec/openjdk.jdk /Library/Java/JavaVirtualMachines/openjdk.jdk
jenv add "$(/usr/libexec/java_home)" # this will always default to the latest version in /Library/Java/JavaVirtualMachines
# or
# jenv add /Library/Java/JavaVirtualMachines/openjdk.jdk
With macOS OpenJDK 21.0.2 installed, for example, either of these commands will add /Library/Java/JavaVirtualMachines/openjdk.jdk/Contents/Home
as a valid JVM. Your JVM directory may vary!
Observe now that this version of Java is added to your jenv versions
command:
$ jenv versions
* system (set by /Users/user/.jenv/version)
21.0
21.0.2
openjdk64-21.0.2
By default, the latest version of Java is your system
Java on macOS.
We'll now set a jenv local VERSION
local Java version for the current working directory. This will create a .java-version
file we can check into Git for our projects, and jenv
will load it correctly when a shell is started from this directory.
$ jenv local 21.0.2
$ cat .java-version
21.0.2
Is JAVA_HOME
set?
$ echo ${JAVA_HOME}
/Users/bberman/.jenv/versions/21.0.2
Yes! Observe that JAVA_HOME
is set to a valid shim directory - this is a result of enabling the export
plugin.
If you executed this commands inside your $HOME
directory, you can now delete .java-version
:
jenv local --unset
# or
rm .java-version
jenv
can set Java versions at 3 levels:
- global (lowest priority)
- local
- shell (highest priority)
Where multiple versions are set, the highest priority setting as above takes effect.
For example if the global version was 17 and the shell version was 11, 11 would be used.
Use jenv global VERSION
to set a global, default Java version:
jenv global 21.0.2
When you next open a shell or terminal window, this version of Java will be the default.
On macOS, this sets JAVA_HOME
for GUI applications on macOS using jenv macos-javahome
. Integrates this tutorial to create a file that does not update dynamically depending on what local or shell version of Java is set, only global.
It can be unset with
jenv global --unset
Use jenv local VERSION
to set the Java used in this folder.
This version will activate whenever you cd
into the follder. This is useful in the root of projects, for example where you would typically run a
./gradlew build
or ./mvnw package
command from.
jenv local 21.0.2
This can be unset with
jenv local --unset
# or
unset .java-version
Use jenv shell VERSION
to set the Java used in this particular shell session:
jenv shell 21.0.2
This can be unset with
jenv shell --unset
# or
unset JENV_VERSION
These common workflows demonstrate how to use jenv
to solve common problems.
Our goal is to have both the latest version of Java and JDK 8 installed at the same time. This is helpful for developing Android applications, whose build tools are sensitive to using an exact Java version.
We'll resume where we left off with Java 21.0.2 installed. Let's install Java 8 from brew and symlink it into the Library folder per the caveats.
brew install openjdk@8
sudo ln -sfn /usr/local/opt/openjdk@8/libexec/openjdk.jdk /Library/Java/JavaVirtualMachines/openjdk-8.jdk
This will install the latest version of Java 8 to a special directory in macOS. Let's see which directory that is:
$ ls -1 /Library/Java/JavaVirtualMachines
openjdk-8.jdk
openjdk.jdk
Observe the openjdk-8.jdk
directory. Your exact version may vary. We cannot retrieve this using /usr/libexec/java_home
, unfortunately. We'll add the Java home directory using jenv
so that it shows up in our jenv versions
command:
$ jenv add /Library/Java/JavaVirtualMachines/openjdk-8.jdk/Contents/Home/
openjdk64-1.8.0.222 added
1.8.0.222 added
1.8 added
$ jenv versions
* system
1.8
1.8.0.222
openjdk64-1.8.0.222
21
21.0
21.0.2
openjdk64-21.0.2
Please contribute your own using a pull request!
Users seem to have issues using jenv
with Fish. Please report any here.