jvm - Java Version Manager

jvm installs, manages and runs different JDKs on a user's system. It finds compatible JDK builds, downloads and verifies them, keeps them in user storage and lets you pick which one to use, either persistently or per command.

default set <selector>, home, env and exec automatically install a JDK when no installed JDK matches the selector. Existing local matches work offline.

The scripts are small, have no dependencies and are meant to be copied into your Java projects. jvm (Bash), jvm.ps1 (native Windows PowerShell 5.1) and jvm.cmd (Windows launcher) need no Java, no package manager and no runtime installation step. That gives you a sure-fire way for your users to build and run your project, even when they don't have Java installed.

On Linux and macOS, the Bash script supports Bash 3.2 and later. On Windows, use current Git Bash, MSYS2 or Cygwin, or Windows PowerShell 5.1.

Using it in your projects

Copy the three scripts jvm, jvm.cmd and jvm.ps1 to the root of your project, and tell your users they can run your application by simply typing:

./jvm x 25+ your_app

This runs your_app with a matching JDK (Java 25 or newer), downloading and installing Temurin if no installed JDK matches. Use .\jvm.cmd on Windows outside Bash.

Or you can configure your PATH and JAVA_HOME for the duration of your shell session by running:

eval $(./jvm env 25+)

(You can run plain ./jvm env if you need a reminder on how to use it with eval)

To avoid repeating the JDK version in every command, add a .jvmrc file to the project root (see Configuration):

java=25+

At which point the previous command can be simplified to:

eval $(./jvm env)

Neat Trick (Runnable .java files)

Take a look at the hello.java file, it has this strange line at the top of the file which, on Linux and Mac, tells your shell how to run the code.

///usr/bin/env ./jvm x 25+ java "$0" "$@" ; exit $?
void main() {
    IO.println("Hello, World!");
}

And then you simply run it like:

./hello.java

(PS: don't forget to make the file executable first with chmod +x hello.java)

Now, you could already do this without jvm, but the nice thing is that now it will even work for people who don't have Java installed. And it will even make sure it's the correct version!

Using it installed

The standalone installers place the tool in ~/.local/bin on every platform. They do not install a JDK. The public URLs become available after the maintainer publishes the first release and Pages site (see publishing).

curl -fsSL https://getjvm.dev/install.sh | bash
# Unattended, with explicit consent to persistent tool PATH only:
curl -fsSL https://getjvm.dev/install.sh | bash -s -- --path --no-java --non-interactive
# Pin a release; rerunning without --version updates to the reviewed latest:
curl -fsSL https://getjvm.dev/install.sh | bash -s -- --version 0.2.0 --no-path --no-java

Windows PowerShell 5.1 (no Bash required):

iex (irm 'https://getjvm.dev/install.ps1')
# For parameters, download and invoke the script:
irm 'https://getjvm.dev/install.ps1' -OutFile "$env:TEMP\jvm-install.ps1"
& "$env:TEMP\jvm-install.ps1" -Version 0.2.0 -Path -NoJava -NonInteractive

From CMD:

powershell.exe -NoProfile -Command "iex (irm 'https://getjvm.dev/install.ps1')"

The installer asks separately about persistent tool PATH and default-JDK JAVA_HOME/PATH setup, showing the target profiles or user registry changes. Answers default to no. Without a terminal, unspecified setup is skipped; --path/--java (PowerShell -Path/-Java) explicitly consent to edits. --no-path/--no-java suppress them. --non-interactive suppresses prompts. Tool downloads are checked against SHA-256 values from the same HTTPS release channel; this checks consistency, not an independent publisher signature.

Unix supports Bash, Zsh, Fish, csh and tcsh. Choose one with --shell bash (or another supported name). Use --profile /absolute/file with --shell for custom startup files or an explicit symlink target. Bash normally updates .bashrc and the existing active login file; Zsh assumes exported ZDOTDIR or HOME; Fish uses XDG_CONFIG_HOME's fish/conf.d/jvm.fish. Unknown shells need manual setup. Exact profile backups are reported. Windows persists only current-user environment values, with raw value/type backups; machine PATH can still take precedence over user Java. No PowerShell profiles are edited.

Legacy BSD csh expands HOME before reading profiles and can crash on homes containing backticks or glob syntax; use tcsh for those homes. Generated setup keeps tool/data paths literal, but cannot change the shell's own initialization.

Open a fresh terminal application or IDE, since a new tab in an old host may inherit stale values. Later startup statements can override setup. This does not configure all GUI or noninteractive programs. Then install Java:

jvm install
jvm x _ java -version

Default-JDK setup can precede the first JDK installation. It names the stable jvm/jdks/default reference under the existing data root. Rerunning the installer updates only its own unmodified files; unrelated or locally modified files cause a conflict. A matching reinstall leaves the payload unchanged. Installer recovery is described in SPEC.md.

You can also copy the scripts manually to a directory on your PATH:

mkdir -p ~/.local/bin
cp jvm jvm.cmd jvm.ps1 ~/.local/bin/
chmod +x ~/.local/bin/jvm

With a manual copy, add that directory to PATH yourself. An installer refuses to take ownership of a manual copy; move it aside before using the installer.

To make the default JDK available in every shell, add this once to your shell profile:

# Unix
export JAVA_HOME="${XDG_DATA_HOME:-$HOME/.local/share}/jvm/jdks/default"
export PATH="$JAVA_HOME/bin:$PATH"

# Git Bash / Cygwin / MSYS2
export JAVA_HOME="$(cygpath -m "${XDG_DATA_HOME:-$HOME/.local/share}/jvm/jdks/default")"
export PATH="$(cygpath -u "${JAVA_HOME}")/bin:$PATH"

Removing the user-wide tool

Read ${XDG_DATA_HOME:-$HOME/.local/share}/jvm/tool-install/record (native Windows path separators on Windows). It records the destination and hashes of owned files. After checking that they still match, remove only its listed jvm file on Unix, or jvm, jvm.ps1, jvm.cmd on Windows. Remove the tool-install directory only when no installer is active and no recovery is pending. Preserve sibling jdks, configuration and cache directories.

On Unix, remove only the # >>> jvm path >>> / # <<< jvm path <<< and # >>> jvm java >>> / # <<< jvm java <<< blocks from the profiles the installer reported. Leave all surrounding user content; remove Fish's jvm.fish only if those blocks are its entire content. Backups are for inspection; do not restore an old profile over later edits.

On Windows, use the user Environment Variables editor to remove only the exact tool-bin and default-JDK-bin entries that the installer added. Remove JAVA_HOME only if it still equals the installer-reported stable default path and you want Java setup removed. Consult the reported raw registry backups to distinguish pre-existing entries. Preserve all other tokens/types; do not restore old environment values over subsequent changes. Refresh terminal applications afterwards. Project copies continue to work independently.

Usage

jvm <command> [options] [selector]

Command	Purpose
available, a [-t] [selector]	Show compatible JDKs available to download
install, i [-d] [-v] [selector]	Download, verify and install a JDK (-d selects the global default; -v selects its major default)
uninstall, u <selector>	Remove an installed JDK
list, l [selector]	Show installed JDKs, even offline
default [<major>], d [<major>]	Query the global or per-major default offline
default set [<major>] <selector>, d set [<major>] <selector>	Set the global or per-major default, installing if needed
home, h [selector]	Print the selected JDK home, installing if needed
env, e [-f] [selector]	Print shell exports for the selected JDK, installing if needed
exec, x <selector> [--] <command> [args...]	Run a command with the selected JDK, installing if needed

exec and x require a selector. Use _ to resolve project java, then user java, then the global default, then Java 25. Configuration errors, failed configured selections and unusable defaults are errors. The _ placeholder is exclusive to exec; it is not a configuration value. Other commands give it no placeholder meaning and retain their existing exact-directory ID rules. home and env use the same precedence when their selector is omitted. jvm default queries the global default; jvm default 21 queries Java 21. After set, one argument is a selector (jvm default set 21 sets the global default using selector 21); two arguments are a scope major and selector (jvm default set 21 temurin-21 sets the Java 21 default). A scope is a positive integer without leading zeros, and the selected JDK must match that major. Queries never install. The d alias uses the same grammar.

One optional -- immediately after the exec selector is skipped. The command must be nonempty; it and every later argument are forwarded unchanged.

Selectors are a major (21), a distro (temurin, for available/list), a distro-major (temurin-21) or a full installed ID. Ranges such as 21+, 21..26 and temurin-21+ are also accepted, except for uninstall.

Examples:

jvm available temurin              # what can be installed
jvm install                        # install the default JDK (Temurin 25)
jvm i -d temurin-21                # install Temurin 21 and make it the default
jvm i -v temurin-25                # install Temurin 25 and select its major default
jvm i -d -v temurin-25             # select both defaults (major first, then global)
jvm list                           # what is installed
jvm default set 21 temurin-21      # set the default for Java 21
jvm home 21                        # print JDK 21's home, installing if needed
eval "$(jvm env temurin-21)"       # use Temurin 21 in the current shell
jvm x 21..26 java -version         # run with the highest matching JDK
jvm x _ java -version              # use configuration/default selection
jvm uninstall temurin-21

Configuration

Optional key=value lines, read from ./.jvmrc and then $XDG_CONFIG_HOME/jvm/config (or ~/.config/jvm/config):

• java=21+ selects the Java major or range.
• distro=graalvm-community selects the distribution.

A command-line selector overrides the project file, which overrides the user file. Configuration does not affect default, available, list, uninstall or help. Run jvm --help for the full reference, and see SPEC.md for the detailed behavior.