commands/installation/clis/install-sdkman.md

Install SDKMAN on Linux

You are helping the user install SDKMAN for managing parallel versions of multiple Software Development Kits.

Your tasks:

1. Check if SDKMAN is already installed:

   • Check: sdk version or which sdk
   • Check for SDKMAN directory: ls -la ~/.sdkman
   • If already installed, ask if they want to update it

2. Check prerequisites: SDKMAN requires:

   • curl: curl --version
   • zip/unzip: which zip unzip
   • bash or zsh shell

   Install missing prerequisites:

   sudo apt update
   sudo apt install curl zip unzip
   

3. Download and install SDKMAN:

   curl -s "https://get.sdkman.io" | bash
   

   The installer will:

   • Install to ~/.sdkman
   • Add initialization to ~/.bashrc or ~/.zshrc
   • Set up sdk command

4. Initialize SDKMAN in current shell:

   source "$HOME/.sdkman/bin/sdkman-init.sh"
   

5. Verify installation:

   sdk version
   sdk help
   

6. Show available SDKs:

   sdk list
   

   Common SDKs available:

   • Java (various distributions: OpenJDK, Graal, Corretto, etc.)
   • Gradle
   • Maven
   • Kotlin
   • Scala
   • Groovy
   • Spring Boot
   • Micronaut
   • And many more

7. Install a few common SDKs (ask user first):

   Java:

   sdk list java
   sdk install java  # installs latest stable
   # Or specific version:
   # sdk install java 17.0.9-tem
   

   Gradle:

   sdk install gradle
   

   Maven:

   sdk install maven
   

8. Show basic SDKMAN usage: Explain to the user:

   • sdk list <sdk> - List available versions of an SDK
   • sdk install <sdk> <version> - Install specific version
   • sdk install <sdk> - Install latest stable
   • sdk uninstall <sdk> <version> - Remove a version
   • sdk use <sdk> <version> - Use version for current shell
   • sdk default <sdk> <version> - Set default version
   • sdk current <sdk> - Show current version in use
   • sdk current - Show all current versions
   • sdk upgrade <sdk> - Upgrade to latest version
   • sdk update - Update SDK list
   • sdk selfupdate - Update SDKMAN itself

9. Configure SDKMAN (optional): Edit ~/.sdkman/etc/config:

   # Auto answer 'yes' to all prompts
   sdkman_auto_answer=true
   
   # Automatically use Java version from .sdkmanrc
   sdkman_auto_env=true
   
   # Check for SDK updates on login
   sdkman_checkup_enable=true
   
   # Automatically selfupdate
   sdkman_selfupdate_enable=true
   

10. Set up project-specific SDK versions: Create .sdkmanrc file in project root:

    java=17.0.9-tem
    gradle=8.4
    maven=3.9.5
    

    Enable auto-env: sdk env or sdk env install

11. Verify PATH and environment:

    which java
    java -version
    echo $JAVA_HOME
    

12. Show how to switch Java versions: Demonstrate:

    sdk list java
    sdk install java 11.0.21-tem
    sdk install java 17.0.9-tem
    sdk use java 11.0.21-tem
    java -version
    sdk default java 17.0.9-tem
    

13. Offline mode (optional): Explain offline mode for when internet is unavailable:

    sdk offline enable
    sdk offline disable
    

14. Flush and clean:

    sdk flush  # Clear caches
    sdk flush temp  # Clear temporary files
    

15. Provide best practices:

    • Run sdk update regularly to refresh SDK lists
    • Run sdk selfupdate to keep SDKMAN current
    • Use sdk current to verify active versions
    • Use .sdkmanrc files for project-specific versions
    • Enable sdkman_auto_env for automatic version switching
    • Use sdk env when entering project directories
    • Keep multiple Java versions for different projects
    • Set sensible defaults with sdk default
    • SDKMAN doesn't require sudo
    • Check ~/.sdkman/candidates/ to see installed SDKs

16. Troubleshooting:

    • If sdk command not found, source the init script
    • Check ~/.bashrc has SDKMAN initialization
    • Restart shell or source bashrc: source ~/.bashrc
    • Check PATH: echo $PATH | grep sdkman
    • Verify SDKMAN directory exists: ls ~/.sdkman

Important notes:

• SDKMAN is user-level, doesn't require sudo
• Each SDK version is kept separate in ~/.sdkman/candidates/
• Can coexist with system Java or other installation methods
• Using sdk use only affects current shell
• Using sdk default affects all new shells
• .sdkmanrc files are project-specific
• SDKMAN is particularly popular in JVM ecosystem
• Bash completion is included