Java Version Manager (JVM)

A lightweight, high-performance, color-coded Windows Batch utility designed to dynamically discover, switch, download, update, and clean up Java Development Kit (JDK) environments without system bloat.

🚀 Features

• Dynamic Vendor Architecture: Menus are dynamically grouped and filtered by vendor (Oracle, Adoptium, GraalVM) to keep your workspace clean and organized.
• Intelligent Background Sorting: Features a built-in, stable bubble-sort algorithm that organizes all discovered JDKs by their major version in descending order, ensuring your newest installations are always at the top of the list.
• Semantic Target Routing: Speak to the tool in human terms. Automatically jump to or install the latest available JDK using targets like jvm latest or jvm lts.
• Directory-based Auto-Switching: Instantly switch to a project's required JDK version by simply running jvm inside any directory containing a .java-version file. The tool parses the file and seamlessly swaps your environment in the background.
• Global Command & Shell Hooks: Features a built-in Settings menu that dynamically injects the jvm command into your system PATH, and can optionally install a native PowerShell Profile Hook to enable true, isolated --session support across multiple terminal tabs.
• Advanced CLI Quick-Switching: Supports intelligent argument parsing to bypass the UI entirely. Quick-switching implicitly prioritizes Oracle > Adoptium > GraalVM for conflict resolution, which can be overridden on the fly with the --vendor flag.
• Oracle JDK Auto-Downloader: Connects directly to official Oracle infrastructure via a transparent, isolated PowerShell instance to pull down and extract modern JDK versions (17, 21, 25, 26, etc.).
• Enterprise-Grade Security: Enforces strict SHA256 checksum verification across all remote download pathways using native .NET Cryptography APIs. Validates payload integrity against official Oracle signature mirrors before extraction, protecting against MITM attacks or corrupted binaries.
• Intelligent Update Checker: Queries official Oracle servers via high-speed HTTP HEAD requests to compare remote build dates against your local release file metadata. Automatically downloads, hot-swaps directories, and patches environment variables in-place if a newer build is found.
• Dynamic Environment Switching: Atomically updates JAVA_HOME and your user/system PATH globally while cleanly updating the environment variables of your active terminal session without spawning double paths.
• The "Phantom Path" Killer: Actively hunts down and scrubs rogue, hardcoded Oracle shortcuts (e.g., Common Files\Oracle\Java\javapath) that installers forcefully inject into the front of your PATH, ensuring JAVA_HOME is always respected.
• Instant Menu Navigation: Uses a smart NEEDS_RESCAN caching architecture to guarantee zero-latency navigation when moving back and forth between interactive submenus.

📋 Prerequisites

• OS: Windows 10 or Windows 11
• Privileges: Administrator rights are required to modify system-level environment variables and registry strings. (The script will automatically request elevation via an optimized UAC pop-up if launched unprivileged).

🛠️ Usage

1. Launch jvm.bat to open the interactive menu, or run it from any terminal.
2. Navigate to Settings (Global Command & Setup) to install the jvm global command.
3. Once installed globally, you can use the following commands from anywhere:

⚡ Quick-Switching (CLI)

Instantly update your JAVA_HOME and system PATH without opening menus. Priority defaults to Oracle > Adoptium > GraalVM for duplicate versions.

• jvm 21 — Switch to JDK 21 (Globally).
• jvm 21 --session — Switch to JDK 21 locally for the current terminal only (requires the PowerShell Profile hook to be installed).
• jvm 21 --vendor adoptium — Override priority and explicitly switch to Adoptium's JDK 21.
• jvm latest — Dynamically switch to the absolute highest installed JDK version.
• jvm lts — Dynamically switch to the highest installed LTS version.
• jvm — If run inside a directory containing a .java-version file, it will silently parse it and auto-switch to that version locally for the current terminal only. If no .java-version file exists, it opens the main interactive terminal UI menu.
• jvm --global — Parses the .java-version file and forces the version switch to apply globally to your system registry.

📥 Installations

• jvm install — Opens the fully interactive Installation Wizard UI.
• jvm install 21 — Initiates the installation of JDK 21 (pauses to prompt you for your preferred Vendor).
• jvm install 21 --vendor oracle — Bypasses all prompts to silently download and install Oracle JDK 21.
• jvm install lts — Prompts you to pick an LTS version (e.g., 17, 21, 25) and then prompts you for your preferred Vendor before installing.
• jvm install lts --latest — Skips the version prompt (locks onto the highest available LTS) but still pauses to prompt you for a Vendor.
• jvm install lts --latest --vendor oracle — 100% automated headless installation of the absolute newest Oracle LTS version (bypasses all menus).
• jvm install 17 --vendor oracle -y — (or --yes) Aggressively bypasses any remaining interactive safety warnings (like Oracle's legacy version caps) for 100% uninterrupted CI/CD automation.

🔄 Updates & Uninstalls

• jvm update — Opens the dynamic, vendor-sorted Updater menu UI.
• jvm update --all — Silently checks and automatically patches all installed JDKs across all vendors.
• jvm update --all --vendor oracle — Silently checks and automatically patches only your installed Oracle JDKs (the --all flag is optional here).
• jvm uninstall — Opens the dynamic, vendor-sorted Uninstaller menu UI.
• jvm uninstall 21 — Headless uninstallation for JDK 21. If multiple vendors are found for the same version, it safely pauses to ask you which vendor you want to remove.
• jvm uninstall 21 --vendor oracle — 100% headless uninstallation specifically targeting the Oracle vendor (bypasses all prompts).

🧹 Global Environment Management

• jvm clear — Instantly wipes JAVA_HOME and purges Java from your PATH.
• jvm link / jvm unlink — Injects or removes the jvm global command from your system PATH.

🎨 Interface Guide

The utility uses native ANSI terminal color formatting to protect system stability:

• 🔹 Cyan [ ACTION ] / [ INFO ] — Indicates system operations, network lookups, and diagnostic information. Version numbers are highlighted in cyan for rapid scanning.
• 🔸 Yellow [ WARNING ] / [ UPDATE ] — Points out non-critical issues, available patches, or destructive prompts.
• 🔺 Red [ ERROR ] — Warns of network failures, blocked file permissions, or locked folders.
• 🔹 Green [ACTIVE] / [ OK ] — Highlights the JDK entry currently actively powering your terminal environment, or signifies a successful operation.
• ◽ Gray — Mutes absolute file paths to reduce terminal clutter.

🛡️ Safety Defaults

To prevent catastrophic accidental deletions on local filesystems, all critical prompts obey standard developer conventions:

• The uninstaller and update prompts use a strict (y/N) validation.
• Pressing Enter or typing anything other than an explicit Y/y acts as an immediate safe abort.
• Custom loops trap premature Ctrl+C commands gracefully, and auto-close countdowns can be interrupted with any keystroke.

📜 Version History

• v0.6.0 (Latest): Massive architecture overhaul. Introduced dynamic Vendor grouping (Oracle, Adoptium, GraalVM) across all menus. Built an optimized, strictly in-memory Bubble Sort algorithm to organize JDKs by newest version. Added .java-version directory-based auto-switching (defaults to session-mode isolation) with an explicit --global CLI override flag. Implemented enterprise-grade SHA256 checksum verification for all JDK downloads using native .NET Cryptography APIs to protect against corrupted payloads. Added semantic CLI routing (jvm latest, jvm lts) and flag overrides (--vendor, --latest, -y). Improved navigation speed via a smart caching NEEDS_RESCAN architecture. Fixed UAC elevation deadlocks, character-encoding path bugs for user profiles, and critical engine parsing bugs that corrupted paths containing exclamation marks (!).
• v0.5.0: Introduced CLI Quick-Switching (jvm <version>) for silent background execution. Added Global Command Installer (Settings menu). Overhauled UI with strict ANSI color hierarchy, path muting, and interruptible auto-close countdowns. Hardened UAC elevation and menu scanning against Windows PATH corruption bugs.
• v0.4.0: Re-engineered dynamic auto-scanner supporting developer toolkits (Scoop, Gradle, IntelliJ), fast release-file parsing, and a massive architectural UI overhaul for robust sub-menu navigation.
• v0.3.0: Relicensed the project to the GNU Affero General Public License v3.0 (AGPL-3.0).
• v0.2.0: Added intelligent update checker (via HTTP HEAD requests), "Update All" bulk-patching, and automated directory hot-swapping.
• v0.1.1: Patched PATH variable corruption bugs and improved delayed-expansion safety protocols during active session switching.
• v0.1.0: Initial Release.

📄 License

Copyright © 2026 DiamTek / Alexéy Shishkin.

This project is licensed under the GNU Affero General Public License v3.0 (AGPL-3.0). See the LICENSE file for details.

Note: Oracle JDK downloads triggered by this tool are subject to the Oracle No-Fee Terms and Conditions (NFTC).