Skip to content
javaup documentation

javaup

Let every Maven project use the right Java toolchain automatically.
Get StartedView on GitHub

Stop reconfiguring your Java environment

Section titled “Stop reconfiguring your Java environment”

A single dev machine often runs Maven builds that target several different Java versions, such as Java 8, Java 17, and Java 21. Without jup, every project switch means manually editing JAVA_HOME and PATH, keeping track of which Java version and which Maven each repository needs, and occasionally dealing with projects that rely on different settings.xml files. It all gets tedious.

javaup (command: jup) takes care of this for you. It automatically detects the Java version a Maven project needs, picks a matching local JDK, and remembers the Maven executable, JDK, and optional settings.xml path that project uses. It then runs the build in a fresh child process, leaving your machine’s environment variables and your current shell completely untouched — safe, convenient, and fast.

flowchart LR
  subgraph before["Before: no jup, all manual"]
    direction TB
    A["switch projects"] --> B["manually edit<br/>JAVA_HOME + PATH"]
    B --> C["remember this project's<br/>Maven + settings.xml"]
    C --> D["manually run the build"]
    D -->|"repeat this routine"| A
  end

  subgraph after["Now: with jup, fully automatic"]
    direction TB
    E["run jup run mvn<br/>from any terminal"] --> F["jup auto-loads<br/>your saved toolchain"]
    F --> G["jup auto-matches<br/>JDK + Maven + settings.xml"]
    G --> H["build in an<br/>isolated process"]
  end

  before ~~~ after

Project-aware

Bind each repository to the Maven executable, JDK, and settings it actually needs, instead of relying on a vague global environment.

Build from anywhere

Select an initialized project and run its build without switching directories or reassembling the environment by hand.

Fits your toolchain

Prefer Maven Wrapper and discover JDKs installed by tools such as SDKMAN! and asdf, or exposed through environment variables and PATH.

Cross-platform

Works on Windows, macOS, and Linux, on both amd64 and arm64.

Just type

Section titled “Just type”
Terminal window
cd /path/to/your/maven-project
jup init
jup status
jup run mvn clean package

Start here

Section titled “Start here”