About Java commands

What is a Java command in the first place?


What kind of processing is done when a Java command is executed in the first place in business?

I looked it up.

How Java commands work

--The java command is a command to start the JVM --The JVM loads the specified class after startup and calls the class's main method -** java command syntax **

java fully qualified class name[Argument argument...]


--The arguments that follow the class name are called ** "startup parameters" ** or ** "command line arguments" **. --Multiple startup parameters can be specified by separating them with a space. --Startup parameters are optional and can be omitted --The data specified as the startup parameter is stored in the String array object by the JVM and passed as an argument of the main method.

Flow when executing java command

--Launch the JVM --Find and load the specified class from the classpath --Create a String type array object to store startup parameters --Execute the main method with a reference to the String array type object that holds the startup parameters as an argument.


public class Main{
   public static void main(String[] args) {
    System.out.println(args[0] + " " + args[1]);


$ java Main red blue grenn

[Dokojava](https://www.google.com/url?sa=t&rct=j&q=1esrc=s&source=web&cd=1cad=rja&uact=8&ved=2ahUKEwj5qq3KlMPsAhWlIqYKHcW1Cl4QFjAAegQIARAC&url=https%3AgQIARAC&url=https Let's actually try it with iJ_00k-0ctsUdsFTbwDe)!

Referenced article (Thank you always.)

[Even beginners can easily understand] Summary of how to use java commands

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