IntelliJ IDEA 2022.1 Help

Run shebang scripts

Starting with version 11, Java provides a way to run self-contained scripts without the need to compile them (https://openjdk.java.net/jeps/330). Furthermore, on Linux and macOS, you can make a Java script executable by specifying the JDK in the first line of the script.

This is called the shebang mechanism. Shebang support in Java comes in handy when you need to write an executable script, but cannot use a scripting language like bash or Python.

Write a script

  1. Create a file without the .java extension.

  2. Start the first line with #! followed by the path to the JDK that will be used to run the script. Use source to specify the language level of the script. Language level 11+ is required.

    Example:

    #!/usr/lib/jvm/openjdk-14.0.1/bin/java --source 11

  3. Write the body of the script. The script can contain multiple classes and use imports from the standard library. The entry point has to be defined as public static void main(String[] args) in the first declared class.

    Below is an example of a valid shebang script:

    #!/usr/lib/jvm/openjdk-14.0.1/bin/java --source 11 import java.util.Locale; class Hello { public static void main(String[] args) { String lang = Locale.getDefault().getLanguage(); System.out.println(Greetings.getGreeting(lang)); } } class Greetings { static String getGreeting(String lang) { switch (lang) { case "fr": return "Bonjour"; case "es": return "Hola"; case "zh": return "Nǐn hǎo"; case "de": return "Guten Tag"; case "pl": return "Dzień dobry"; case "el": return "Yassas"; case "sv": return "God dag"; default: return "Hi"; } } }
  4. Make sure that the script file is executable using the chmod +x command.

Run a script

  • Click the Run icon in the gutter or press Ctrl+Shift+F10.

    Shebang run
  • Create a run/debug configuration. This can be useful if you want to pass parameters to your script, debug it, or run it as part of a compound workflow.

Debug a script

  1. Create a run/debug configuration for the script and add a VM option to load the debug agent.

  2. Attach to the process using the Remote JVM debug run/debug configuration.

Last modified: 14 March 2022