The Scanner class retrieves data from the user and saves it to a variable.

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in); // an object of the Scanner class with System.in assigned to it

        String x = input.next(); // retrieving a string from the user
        System.out.println(x);

        int y = input.nextInt(); // retrieving an integer from the user
        System.out.println(y);

        double z = input.nextDouble(); // retrieving a decimal from the user
        System.out.println(z);
    }
}