Error: Could not find or load main class Principal




I copied the custom java builder and runner from
The build works and sends the .class file to .bin/ but the runner does not work.

I searched in google but nothing helped me.

this is my class:

class Principal{
    public static void main(String[] args){
        System.out.println("Hello World");

In the console, using javac and java, it works.

Thanks, hope someone can help.