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jenv lets you choose among Java versions already installed on your computer, with a default for your shells, a project-specific version, or a temporary shell override. It does not install Java, and it does not manage versions of every development tool. Install a JDK separately, register it with jenv, then select the version you need.
What jenv manages—and what it does not
jenv is a Java environment selector. It switches the Java version used in different contexts and can set Java environment variables. The official jenv README is explicit: “jenv does not, by itself, install java for you.” You need at least one JDK installed before jenv can select it.
jenv also offers optional plugins for selected build tools, including Gradle, Maven, Ant, Leiningen, and sbt. These integrations expose documented options for those tools; they do not turn jenv into a general version manager for all development software.
Install jenv and initialize your shell
The jenv README documents Homebrew and MacPorts installation routes for macOS, plus a source-install route for Linux. Choose the route for your operating system in the official installation instructions; avoid assuming that a command or path for one platform applies to another.
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After installation, configure your shell to put jenv’s bin directory on PATH and evaluate its initialization command. The README provides bash and zsh examples; its fish setup is labeled untested.
- Open the startup file for the shell you use, following the corresponding example in the jenv README.
- Add jenv’s
bindirectory toPATH, then addeval "$(jenv init -)". - Save the file and restart the terminal or reload the shell configuration.
- Run
jenvto check that the command is available.
Register installed JDKs with jenv
Use jenv add PATH_TO_JVM_HOME to register an installed Java environment. Replace the example placeholder with the home path for a JDK on your machine. That path depends on the operating system and how you installed Java. On macOS, the README demonstrates jenv add $(/usr/libexec/java_home); it is an example for macOS, not a universal path.
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Check what jenv can use with jenv versions. The output lists registered choices and aliases. Select an alias shown on your own system rather than copying a version label from an example: aliases depend on the Java installations you have registered.
Choose whether Java selection is global, project-specific, or temporary
jenv provides three selection scopes. The project documents their precedence as shell over local over global, so a temporary shell choice overrides a project setting, and a project setting overrides the default.
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| Command | Scope | Persistence and use |
|---|---|---|
jenv global VERSION |
Default for your shells | Remains the global choice until you change it. |
jenv local VERSION |
Current directory and its project descendants | Writes a .java-version file in the current directory. |
jenv shell VERSION |
Current shell session | Temporary override with the highest precedence. |
Set your default Java version
Run jenv global VERSION, substituting an alias listed by jenv versions. This sets the default when neither a local project setting nor a shell override takes precedence.
Set a version for one project
From the project directory, run jenv local VERSION. jenv writes .java-version; you can commit that file so the project’s selection is present when a shell starts in that directory. To remove the local selection, run jenv local --unset.
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Use a temporary version in the current shell
Run jenv shell VERSION to select a version for the current shell session. Clear that override with jenv shell --unset. Because this scope takes priority over both local and global settings, it is useful for a one-off command or check without changing the project file or your default.
Export JAVA_HOME and JDK_HOME when a tool needs them
Some applications and build tools read environment variables such as JAVA_HOME or JDK_HOME rather than relying only on the Java command resolved through jenv. In that case, enable jenv’s export plugin using the plugin instructions in the project README; it sets and exports those variables.
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Optional plugins also set documented option variables for Gradle, Maven, Ant, Leiningen, and sbt. Enable only the integration relevant to your workflow. If a tool still uses an unexpected Java installation, check the active jenv scope and whether the tool reads an exported variable.
Check current release information before relying on a specific version
jenv’s official releases page is the place to check release history. The project documentation cited here does not establish a latest release number or a complete compatibility matrix, so verify current project guidance for your operating system and shell rather than assuming support for a particular combination.
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