install-jdk-on-steam-deck

• How it works
• Usage
• How to uninstall it
• Troubleshooting
• TO-DO

How it works

By default, the SteamDeck has a read-only immutable OS file system, which means that you can't simply install anything using the pacman package manager that comes with the OS (arch linux), since it would modify the OS file system.

So in order to install anything outside the Software Center (which installs programs in a way that doesn't affect the OS by using flatpak), you have to modify things in you home directory, which shouldn't mess up with the OS and break the system.

Taking this into account, the script located in the scripts directory of this repository will:

• Download the official JDK compressed file into your home directory, more specifically into ~/.local/jdk
• Exec a checksum of the file using the official sha256 checksum
• Extract the file into the JDK's own version-specific directory (e.g., ~/.local/jdk/jdk-17.0.1/, ~/.local/jdk/jdk-21.0.5/, ~/.local/jdk/jdk-24.0.1/, etc.)
• Add environment variables to your ~/.profile and source it in your bashrc for each installed version:
  • JAVA_{VERSION}_HOME: Version-specific home (e.g., JAVA_17_HOME, JAVA_21_HOME)
  • JAVA_HOME: Points to your chosen default version (with smart recommendations)
  • PATH: Adds each version's bin directory so all executables are available

Optimized and Efficient: The installer and uninstaller scripts have been optimized for maximum efficiency while preserving all functionality:

• Compact Code: Streamlined from 800+ lines to ~620 lines (installer) and 447 to 256 lines (uninstaller)
• Faster Execution: Reduced redundancy and improved performance
• Maintainable: Cleaner, more readable code structure
• Zero Functionality Loss: All features and safety measures preserved

Dynamic Version Discovery: The scripts automatically discover and support new JDK versions without requiring updates. They dynamically fetch the latest available versions from official sources including Oracle, OpenJDK, and Eclipse Adoptium.

Multi-Version Support: You can install multiple JDK versions side-by-side. Each version gets its own directory and environment variables, allowing you to easily switch between Java versions for different projects. The script also supports installing all supported JDK versions at once for maximum compatibility.

Future-Proof Design: The scripts automatically adapt to new JDK releases without requiring manual updates, supporting versions 8 through the latest available releases (currently up to JDK 24+).

By adding the variables to .profile instead of .bashrc we ensure to be more "shell agnostic", so if you run a script in another shell like sh or launch a graphical program, it should read the environment variables defined there.

.profile is "manually" sourced in .bashrc since bash will try to source first .bash_profile and .bash_login if they exist. To learn about this:

• man sh: Invocation
• bash manual: Invoked with name sh.

With this, you will have a local installation of java and even better, you can install multiple versions and then point to the one you need.

Supported JDK Versions: The installer dynamically discovers and supports all current JDK versions including:

• JDK 8: Eclipse Adoptium (Temurin)
• JDK 11-24+: Latest versions from Oracle JDK and OpenJDK
• Automatic Discovery: New versions are automatically detected and supported without script updates
• Multiple Providers: Supports Oracle, OpenJDK, and Eclipse Adoptium sources

Smart Version Detection: The script intelligently detects which JDK versions are already installed by scanning for Java executables and parsing their version output. It only shows uninstalled versions in the installation menu, making it clear what options are available.

Intelligent Menu System:

• Dynamic Version Discovery: Automatically detects the latest available JDK versions from official sources
• No JDKs installed: Shows all available versions for installation
• Some JDKs installed: Displays installed versions, shows only uninstalled versions for installation, and includes a "Skip to change defaults" option
• All JDKs installed: Automatically skips to default version selection
• Future-Proof: Automatically supports new JDK releases without requiring script updates

Smart Default Selection: When multiple JDK versions are installed, the script presents an interactive menu to choose your default Java version, automatically recommending the latest (highest numbered) version. You can simply press Enter to accept the recommended default or choose any other installed version.

Usage

The script supports both interactive mode and environment variable mode for version selection.

Interactive Mode (Recommended for new users):

Simply run the script without specifying a version, and it will present an interactive menu:

git clone https://github.com/FlyingEwok/install-jdk-on-steam-deck.git && \
./install-jdk-on-steam-deck/scripts/install-jdk.sh

The script will show available versions dynamically discovered from official sources:

=== JDK Installer for Steam Deck ===

Please select which JDK version you would like to install:

  1) JDK 8 (Eclipse Adoptium)
  2) JDK 11 (Oracle JDK)
  3) JDK 17 (Oracle JDK) 
  4) JDK 21 (Oracle JDK)
  5) JDK 23 (Oracle JDK)
  6) JDK 24 (Oracle JDK - recommended)
  7) Install All Available JDK Versions
  8) Install All Remaining JDK Versions (if some already installed)

Enter your choice (1-8) [default: 6 for latest version]:

If some JDKs are already installed, the script will show which ones are installed and only list uninstalled versions:

=== JDK Installer for Steam Deck ===

Already installed JDK versions: 21 8

Please select which JDK version you would like to install:

  1) JDK 11 (Oracle JDK)
  2) JDK 17 (Oracle JDK)
  3) JDK 23 (Oracle JDK)
  4) JDK 24 (Oracle JDK - recommended)
  5) Install All Remaining JDK Versions
  6) Skip installation and change default Java version

Enter your choice (1-6) [default: 4 for latest available]:

If all JDKs are already installed, the script will automatically proceed to default version selection without showing an installation menu.

Environment Variable Mode (For automation/scripts):

You can choose which version to install by setting the variable JDK_VERSION before executing the script. This method is perfect for automated installations and CI/CD pipelines and supports dynamic version discovery.

When using environment variables:

• No interactive prompts: The script runs completely automated
• Dynamic version support: Automatically works with the latest available JDK versions
• Smart default selection: Automatically sets the latest (highest numbered) installed JDK version as the default
• Install all versions: Use JDK_VERSION=ALL to install all currently available JDK versions at once
• Install remaining versions: Use JDK_VERSION=REMAINING to install only uninstalled versions
• Skip to defaults: Use JDK_VERSION=SKIP_TO_DEFAULT to skip installation and just change the default version

Install specific versions dynamically discovered:

To install JDK 8 (Eclipse Adoptium):

git clone https://github.com/FlyingEwok/install-jdk-on-steam-deck.git && \
JDK_VERSION=8 ./install-jdk-on-steam-deck/scripts/install-jdk.sh

To install JDK 11 (Oracle JDK):

git clone https://github.com/FlyingEwok/install-jdk-on-steam-deck.git && \
JDK_VERSION=11 ./install-jdk-on-steam-deck/scripts/install-jdk.sh

To install JDK 17 (Oracle JDK):

git clone https://github.com/FlyingEwok/install-jdk-on-steam-deck.git && \
JDK_VERSION=17 ./install-jdk-on-steam-deck/scripts/install-jdk.sh

To install JDK 21 (Oracle JDK):

git clone https://github.com/FlyingEwok/install-jdk-on-steam-deck.git && \
JDK_VERSION=21 ./install-jdk-on-steam-deck/scripts/install-jdk.sh

To install JDK 23 (Oracle JDK):

git clone https://github.com/FlyingEwok/install-jdk-on-steam-deck.git && \
JDK_VERSION=23 ./install-jdk-on-steam-deck/scripts/install-jdk.sh

To install JDK 24 (Oracle JDK):

git clone https://github.com/FlyingEwok/install-jdk-on-steam-deck.git && \
JDK_VERSION=24 ./install-jdk-on-steam-deck/scripts/install-jdk.sh

Note: The script automatically discovers the latest available versions, so newer JDK versions (25, 26, etc.) will be supported automatically as they're released.

To install ALL currently available JDK versions at once:

git clone https://github.com/FlyingEwok/install-jdk-on-steam-deck.git && \
JDK_VERSION=ALL ./install-jdk-on-steam-deck/scripts/install-jdk.sh

To install only remaining (uninstalled) JDK versions:

git clone https://github.com/FlyingEwok/install-jdk-on-steam-deck.git && \
JDK_VERSION=REMAINING ./install-jdk-on-steam-deck/scripts/install-jdk.sh

To skip installation and just change the default Java version (automatically sets latest as default):

git clone https://github.com/FlyingEwok/install-jdk-on-steam-deck.git && \
JDK_VERSION=SKIP_TO_DEFAULT ./install-jdk-on-steam-deck/scripts/install-jdk.sh

Which Mode Should You Use?

• Interactive Mode: Best for most users, especially first-time installations. Provides clear options and guidance. Automatically detects installed versions and shows relevant options.
• Environment Variable Mode: Perfect for automation, scripts, CI/CD pipelines, or when you know exactly which version you need. Automatically sets the latest version as default without prompting.

Using specific versions in your projects: After installation, you can reference specific versions using the dynamically created environment variables:

• $JAVA_8_HOME/bin/java for JDK 8
• $JAVA_11_HOME/bin/java for JDK 11
• $JAVA_17_HOME/bin/java for JDK 17
• $JAVA_21_HOME/bin/java for JDK 21
• $JAVA_23_HOME/bin/java for JDK 23
• $JAVA_24_HOME/bin/java for JDK 24
• And so on for any newly discovered versions...

Or simply use java which will use the default JAVA_HOME (your chosen default version).

Default Java Version Selection: After installing multiple JDK versions, the behavior depends on how you run the script:

Interactive Mode: The script will prompt you to choose which version should be the default:

Multiple Java versions detected. Please choose which one should be the default:
  1) JDK 8
  2) JDK 11  
  3) JDK 17
  4) JDK 21
  5) JDK 24 (recommended - latest version)

Enter your choice (1-5) [default: 5 for JDK 24]: 

• Press Enter: Accept the recommended latest version (JDK 24 in this example)
• Choose a number: Select any specific version as your default
• Latest is recommended: The script automatically identifies and recommends the highest version number

Environment Variable Mode: The script automatically sets the latest (highest numbered) installed JDK version as the default without prompting (defaults to latest). This ensures automated installations work smoothly without user interaction.

Re-running with existing versions: The script intelligently handles scenarios when you already have JDK versions installed:

1. Detects existing installations: Automatically scans for installed JDK versions and displays them
2. Shows only relevant options: Only displays uninstalled versions in the installation menu
3. Skip installation option: Provides a "Skip installation and change default Java version" option when versions are already installed
4. Automatic behavior for complete installations: If all supported versions are installed, automatically proceeds to default version selection
5. Updates environment variables: Refreshes your .profile with all currently installed JDKs
6. Preserves existing installations: Never overwrites or damages existing JDK installations

This means you can re-run the script at any time to:

• Install additional JDK versions alongside existing ones
• Change your default Java version
• Refresh your environment setup
• Use the "Skip to defaults" option to quickly change defaults without installing anything

How to uninstall it

Optimized Interactive Uninstall Script (Recommended): The repository includes an efficient uninstall script that has been optimized from 447 lines to just 256 lines while preserving all functionality:

# Run the interactive uninstall script
./install-jdk-on-steam-deck/scripts/uninstall-jdk.sh

The uninstall script will:

1. Dynamically detect all installed JDK versions (no hardcoded version limits)
2. Present an efficient interactive menu with options to:
   • Remove individual JDK versions
   • Remove all JDK installations at once
   • Cancel the operation safely
3. Intelligently clean up environment variables from your .profile
4. Smart profile management: Update remaining installations if you only remove some versions
5. Safety confirmations: Require explicit confirmation before any destructive operations
6. Default version handling: Automatically prompt for new default when current default is removed

Example menu:

=== JDK Uninstaller for Steam Deck ===

Found the following JDK installations:
  1) JDK 8 (/home/deck/.local/jdk/jdk8u422-b05)
  2) JDK 11 (/home/deck/.local/jdk/jdk-11.0.25)
  3) JDK 17 (/home/deck/.local/jdk/jdk-17.0.13)
  4) JDK 21 (/home/deck/.local/jdk/jdk-21.0.5)
  5) JDK 24 (/home/deck/.local/jdk/jdk-24.0.1)
  6) Remove ALL JDK installations
  7) Cancel

Enter your choice (1-7):

Manual Uninstall (Alternative):

To remove a specific JDK version:

# Remove JDK 17 installation (replace with actual directory name)
rm -rf ~/.local/jdk/jdk-17.0.1

# Remove JDK 21 installation (replace with actual directory name)
rm -rf ~/.local/jdk/jdk-21.0.5

# Remove JDK 24 installation (replace with actual directory name)
rm -rf ~/.local/jdk/jdk-24.0.1

# Or find the exact directory names first:
ls ~/.local/jdk/

To remove all JDK installations:

# Remove the entire installation directory
rm -rf ~/.local/jdk

To clean up environment variables:

# Edit ~/.profile and remove the JDK-related lines:
# export JAVA_8_HOME=...
# export JAVA_16_HOME=...
# export JAVA_17_HOME=...  
# export JAVA_HOME=...
# export PATH=$PATH:...jdk.../bin
nano ~/.profile

# Optionally, remove the line added to your bashrc:
# [[ -f ~/.profile ]] && source ~/.profile
# (This line is harmless and will simply do nothing if ~/.profile doesn't exist)

Switching default Java version:

• Easy method: Re-run the installer script for any installed version - it will prompt you to choose a new default
• Manual method: Edit ~/.profile and modify the export JAVA_HOME= line to point to your preferred version's JAVA_{VERSION}_HOME

Safe Installation Process: Both installer and uninstaller scripts include robust error handling that only affect files related to the current operation, preserving all your existing JDK installations if something goes wrong. The optimized scripts maintain all safety measures while being more efficient.

Troubleshooting

Debug Mode: If you encounter issues with JDK detection (e.g., installed JDKs not being recognized), you can run the script in debug mode to get detailed information about what's happening:

DEBUG=1 ./scripts/install-jdk.sh

This will show:

• Which directories are being checked for JDK installations
• Java version output from each detected installation
• Detection results for each JDK version
• Any errors encountered during the detection process
• Installation directory status and contents

Common Issues:

1. JDKs not detected: This can happen if:

   • Java executables are corrupted or incomplete
   • Directory permissions are incorrect
   • The Java version string format is unexpected

   Run with DEBUG=1 to see exactly what's happening during detection.

2. Installation fails: Make sure you have enough disk space and proper write permissions to ~/.local/jdk/

3. Environment variables not working: After installation, make sure to either:

   • Log out and log back in, OR
   • Run source ~/.profile in your current terminal

4. Script shows wrong installed versions: The detection relies on executable Java binaries. If a JDK installation is incomplete or corrupted, it may not be detected properly.

Getting Help: If debug mode shows unexpected behavior, please include the debug output when reporting issues. This helps identify platform-specific detection problems and makes troubleshooting much faster.

Standalone Debug Script: For more detailed troubleshooting, you can create a debug script to check the detection system:

# Create a debug script to test detection
DEBUG=1 bash -c 'source ./scripts/install-jdk.sh; check_installed_versions'

This provides comprehensive information about:

• Installation directory status and contents
• Java executable availability and permissions
• Version detection pattern matching
• System information and environment variables

Share the output when reporting detection issues for faster troubleshooting.

TO-DO

• Add an uninstall script or option ✅ COMPLETED
• Add support for java 8 ✅ COMPLETED
• Add support for multiple JDK versions ✅ COMPLETED
• Add interactive default Java version selection ✅ COMPLETED
• Improve error handling to preserve existing installations ✅ COMPLETED
• Add support for switching between installed JDK versions easily ✅ COMPLETED
• Add intelligent version detection to avoid reinstalling existing versions ✅ COMPLETED
• Add smart menu system that only shows relevant installation options ✅ COMPLETED
• Add "Skip to change defaults" option for existing installations ✅ COMPLETED
• Optimize and condense scripts for better performance and maintainability ✅ COMPLETED
• Add dynamic version discovery for future-proof JDK support ✅ COMPLETED
• If you want anything added, just let me know by opening an issue