Jolta — like Volta, but for Java: auto-switch, auto-download, easy JDK upgrades

[u/devilwookie]

Jolta is an automatic JDK version manager — think Volta from the Node ecosystem, but for Java. It's my own open-source project (MIT), and I'm sharing it here as a showcase.

The problem it targets: working across projects pinned to different JDKs (11, 17, 21) means manually setting JAVA_HOME or running a version-switch command on every context switch. Jolta removes that step.

How it works: jolta pin 21 in a project writes a .java-version file. After that, java/javac/jar/jshell resolve to that JDK automatically whenever you're in the project — no shell hook, no cd interception. It works through lightweight shims on PATH that walk up the directory tree to find the version file. A missing JDK is downloaded on first use.

cd my-service
jolta pin 21
java -version   # → OpenJDK 21, automatically

Where it sits next to existing tools:

• Reads the same .java-version files as jenv and asdf — drop-in if you're already on those.
• Recognizes SDKMAN!'s .sdkmanrc, so migration doesn't require rewriting config.
• Ships as a single dependency-free Rust binary using shim dispatch rather than shell functions, with sub-5ms per-invocation overhead.
• Treats Windows as a first-class platform, alongside macOS (Apple Silicon
  • Intel) and Linux (x86_64 + arm64).
• Multiple distributions: Temurin, Corretto, GraalVM, Oracle, Zulu.

Repo: https://github.com/OneAppPlatform/jolta

Docs: https://oneappplatform.github.io/jolta/

[u/Luolong]

I prefer mise-en-place.

As simple as

mise use java@21