java classes and methods

// this might help you understand how classes work
public class MathTest {

    public static void main(String[] args) {

        class MathAdd {

            int num1;
            int num2;

            public int addNumbers() {

                int addThemUp = num1 + num2;
                return addThemUp;
            }
        }

        MathAdd addition = new MathAdd(); // create a new instance of the class

        // you can access variables from the class 
        addition.num1 = 10; 
        addition.num2 = 20;

        // and use the method from the class to add them up
        System.out.println(addition.addNumbers());

    }
}

import java.lang.Math;
import java.util.Scanner;

public class HelloWorld {
  public static void main(String[] args) {
    class ResultNumberShape {

            double number;

            public boolean isSquare(double number) {

                double result = Math.sqrt(number);
                return ((result - Math.floor(result)) == 0);

            }
        }

        ResultNumberShape checkNumber = new ResultNumberShape();

        System.out.println("Enter any number:");
        Scanner scanner = new Scanner(System.in);
        double num = scanner.nextDouble();

        scanner.close();

        if (checkNumber.isSquare(num)) {
            System.out.println(num + " is a sqaure number!");
        } else {
            System.out.println(num + " is not a square!");
        }
    
  }
}