Spring Shell

Spring Shell, as one of Spring family, is a framework that helps you to create an CLI application with its own infrastructure.

This infrastructure creates a REPL (Read, Eval, Print Loop) app where you can define and implement commands in a way that’s idiomatic to Spring.

As of 3.4.0, it provides advanced features such as

• Parsing
• Tab Completion
• UI/UX on CLI (Such as colorization, ASCII-art, …)

Let’s say you want to write an interactive CLI application with Spring Shell. Just like other spring projects, you could easily initialize the project for Spring Shell, using Spring Initializer.

You can define a class, Commands that holds your own commands with a @ShellComponent annotation.

@ShellComponent  
public class Commands {  
    @ShellMethod(key = "hello-world")  
    public String helloWorld(@ShellOption(defaultValue = "Spring") String arg) {  
        return "Hello World! " + arg;  
    }  
}

Inside the Commands class, let’s define a method that represents an command, with a @ShellMethod annotation. A value for key property is used as a selector for this command.

Beside built-in commands, you can see your hello-world command and execute it.

$ 2025-07-20T02:15:53.270+09:00  INFO 56013 --- [spring-shell-test] [           main] .n.b.a.SpringShellTestApplication : Started SpringShellTestApplication in 1.094 seconds (process running for 1.39)
shell:>help
AVAILABLE COMMANDS
 
Built-In Commands
       help: Display help about available commands
       stacktrace: Display the full stacktrace of the last error.
       clear: Clear the shell screen.
       quit, exit: Exit the shell.
       history: Display or save the history of previously run commands
       version: Show version info
       script: Read and execute commands from a file.
 
Commands
       hello-world: 
 
shell:>hello-world
Hello World! Spring
shell:>hello-world --arg Boot
Hello World! Boot

You can also provide an argument for the command with a --arg option (value=Boot)

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Note

I’m trying to write a program like a bot that automates replying, and visiting followers on a blog platform. Before I get caught up in frontend things, I’d like to focus on core business logic and domain models. Then I discovered this Spring Shell, and was very tempted to give it a try :)

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Refs.

• https://docs.spring.io/spring-shell/reference/index.html