javm

README

javm is a fast, cross‑platform Java version manager (fork of jabba) focused on a frictionless install and switch workflow for JDKs on Linux, macOS and Windows.

Features

• Install & switch between multiple JDK distributions (Zulu, OpenJDK, GraalVM, Temurin, etc.) using semver ranges
• Per‑project JDK via .java-version
• Remote discovery (DiscoAPI integration) + custom URLs
• Supports semantic version ranges (1.8.x, ~17.0.2, >=21 <22)
• Clean removal (uninstall, deactivate) without touching system JDK
• Static Go binary: fast cold start and no additional dependency

Installation

You can install javm using the provided install scripts. They automatically detect your platform and architecture, and support different release channels:

• latest: install from the latest GitHub Release (default)
• nightly: install the most recent development build
• Specific version: e.g. v0.1.0

Linux and macOS

By default, installs the latest release to ~/.javm.

To install the latest release:

curl -fsSL https://javm.dev/install.sh | bash

To install a specific version or channel:

curl -fsSL https://javm.dev/install.sh | bash -s nightly
curl -fsSL https://javm.dev/install.sh | bash -s v0.1.0

Windows

By default, installs the latest release to %LOCALAPPDATA%\Programs\javm.

To install the latest release:

irm https://javm.dev/install.ps1 | iex

To install a specific version or channel:

iex "& { $(irm https://javm.dev/install.ps1) } nightly"
iex "& { $(irm https://javm.dev/install.ps1) } v0.1.0"

Shell Setup

To enable javm in your shell, you need to evaluate the output of javm init <shell>.

Bash

Add this to your ~/.bashrc or ~/.zshrc:

eval "$(javm init bash)"

Zsh

Add this to your ~/.zshrc:

eval "$(javm init zsh)"

Fish

Add this to your ~/.config/fish/config.fish:

javm init fish | source

PowerShell

Add this to your profile file:

iex "$(javm init pwsh)" 

[!TIP] To check the path to your PowerShell profile file, run:

echo $PROFILE

Post Setup

After editing your profile or config, restart your shell or reload your profile to apply the changes.

Usage

Listing / Searching

javm ls-remote                      # list all available JDKs
javm ls-remote zulu@~1.8.60         # narrow by distribution & semver range
javm ls-remote "*@>=1.6.45 <1.9" --latest=minor  # show only latest minors

Installing

javm install zulu@1.8               # Zulu OpenJDK 8 (latest matching)
javm install zulu@~1.8.144          # same as zulu@>=1.8.144 <1.9.0
javm install temurin@17             # Temurin 17 LTS
javm install graalvm@21             # GraalVM
javm install openjdk@21             # Upstream OpenJDK
javm install 1.8.0-custom=https://example.com/dist.tar.gz

Using / Switching

javm ls                              # list installed
javm use zulu@1.8
javm use temurin@17
javm deactivate                      # restore previous JAVA_HOME / PATH

Per‑Project Version (.java-version)

Create a .java-version in your project root:

17

Then:

javm use   # picks version from .java-version

Aliases

javm alias default 17       # sets default JDK for new shells
javm alias list

Linking Existing System JDK

javm link system@1.8.72 /Library/Java/JavaVirtualMachines/jdk1.8.0_72.jdk

Uninstall

javm uninstall zulu@1.8

Development

Prerequisite: Go 1.24.x

git clone https://github.com/felipebz/javm
cd javm
go test ./...
go build -o javm .
./javm --help

FAQ

Q: Does it override my system Java?
No. javm use adjusts your shell PATH and JAVA_HOME in that session.

Q: How do I revert to the system JDK?
Run javm deactivate or open a new shell (if no default alias points elsewhere).

Q: Can I pin a project JDK?
Yes: Create a .java-version with the JDK version then javm use inside that directory.

Q: Why not install “globally”?
Global changes (e.g. system alternatives, registry edits) vary by OS and often require sudo/admin; javm keeps things user‑scoped and portable.

License

Apache-2.0. See LICENSE.