Run echo example from Jshell

Question

I read such a command line arguments example:

public class Echo {
    public static void main (String[] args) {
        for (String s: args) {
            System.out.println(s);
        }
    }
}

It runs properly from command line, how could I run it from Jshell?

jshell> Echo.main testing
|  created variable testing, however, it cannot be referenced until class main is declared

It report error that failed to be referenced.

Are you running that class definition in jshell? After that you can simply run Echo.main(new String[] {"arg1", "arg2"}) — Harry Jones, Sep 08 '20 at 08:18

score 2 · Accepted Answer · answered Sep 08 '20 at 08:51

You invoke it as any other static method:

Echo.main(new String[] { "hello", "world" });

Full session:

$ jshell
|  Welcome to JShell -- Version 11.0.8
|  For an introduction type: /help intro

jshell> public class Echo {
   ...>     public static void main (String[] args) {
   ...>         for (String s: args) {
   ...>             System.out.println(s);
   ...>         }
   ...>     }
   ...> }
|  created class Echo

jshell> Echo.main(new String[] { "hello", "world" });
hello
world

Note that you can declare your main method as follows:

public static void main(String... args) { ... }

This is binary compatible with String[] args syntax, but would allow you to invoke it as follows:

Echo.main("hello", "world");

Run echo example from Jshell

1 Answers1