Command Line arguments in Spring boot outside main problem

Question

I am trying to get command line arguments outside the main method in spring boot application, i tried many methods but none of them is working. I am using spring boot 2.4.5. Following is my code:

package com.example;

import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class MainClass implements ApplicationRunner {
    public static void main(String[] args){
        SpringApplication.run(MainClass.class);
        for (String arg : args) System.out.println("MAIN::::"+arg);
    }

    @Override
    public void run(ApplicationArguments args) throws Exception {
        System.out.println("# NonOptionArgs: " + args.getNonOptionArgs().size());

        System.out.println("NonOptionArgs:");
        args.getNonOptionArgs().forEach(System.out::println);

        System.out.println("# OptionArgs: " + args.getOptionNames().size());
        System.out.println("OptionArgs:");

        args.getOptionNames().forEach(optionName -> {
            System.out.println(optionName + "=" + args.getOptionValues(optionName));
        });
    }
}

Here is the output for passing argument: iamnonoption --app.name=CmdRulez --app.hosts=abc,def,ghi --app.name=2 :

# NonOptionArgs: 0
NonOptionArgs:
# OptionArgs: 0
OptionArgs:
MAIN::::iamnonoption
MAIN::::--app.name=CmdRulez
MAIN::::--app.hosts=abc,def,ghi
MAIN::::--app.name=2

Why ApplicationArguments is not getting any arguments?

Answer 1

Change :

SpringApplication.run(MainClass.class);

To:

SpringApplication.run(MainClass.class, args);

Reference