如何在另一个类中使用静态类中的变量？

Question

I's trying to build an encoder like the "Enigma Machine" and I have this code so far where I'm trying to get comboOne() to use the "s" variable from main():

import java.io.*;

public class main
{
    public static void main(String[] args) throws IOException
    {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("What would you like to encode?");
        String s = br.readLine();

        s.toCharArray();
        System.out.println(s);

        //comboOne comboOne = new comboOne();
    }
}

Just to encode one letter I've written this:

public class comboOne extends main
{
    main m = new main();
    char message = s.toCharArray();
        if(message == 'a')
    {
        System.out.println('b');
    }
}

I am quite new so apologies if I am making an obvious mistake but I think this would be a fun challenge for myself. Please send help and thanks for helping :)

Answer 1

Add outside your Main.main method

public static String s;

Then use Main.s to access the String in a static way. Since it is static it does not need to be instantiated an can directly be called from the class.