2 Problems. Unable to retrieve correct output for area of Triangle, and unsure of what else-if state to use so my input can recognize a square

Here is my TestShape file. As you can see depending on how many arguments I provide through the command line or terminal, it will create the following object and call getDetails(). My first problem is that I am unsure on what else-if condition to use for the Square as both, Square and Circle eg. This is for circle -->(args.length == 1) require one user inputted variable to create their objects.

My second problem is that when I trigger the Triangle else-if statement, and it calls the t.getDetails() it returns everything correct except I don't receive a value for the area. Check the other files down below.

Here is my output for the Triangle trigger:

Input: java TestShape 10 10 20 <ENTER>

Output:

Type: Triangle

Side1: 10

Side2: 10

Side3: 20

Perimeter: 40.0

Area: -0.0

//TestShape.java
public class TestShape {
    public static void main(String[] args) {
        if (args.length == 1) {
            Circle c = new Circle(Integer.parseInt(args[0]));
            c.getDetails();
            
        } else if (args.length == 2) {
            Rectangle r = new Rectangle(Integer.parseInt(args[0]), Integer.parseInt(args[1]));
            r.getDetails();
            
        } else if (args.length == 3) {
            Triangle t = new Triangle(Integer.parseInt(args[0]), Integer.parseInt(args[1]), Integer.parseInt(args[2]));
            t.getDetails();
            
        } else if (/* Unsure on what to write here.*/) { 
            Square s = new Square(Integer.parseInt(args[0]));
            s.getDetails();

        } else {
            System.out.println("Invalid Input");
        }
    }
}

//Triangle.java
public class Triangle implements Shape {
    public int side1;
    public int side2;
    public int side3;

    public Triangle(int side1, int side2, int side3) {
        this.side1 = side1;
        this.side2 = side2;
        this.side3 = side3;
    }
    public double s = (side1 + side2 + side3)/2;

    @Override
    public double getPerimeter() {
        return side1 + side2 + side3;
    }

    @Override
    public double getArea() {
        return Math.sqrt(s * (s - side1) * (s - side2) * (s - side3));
    }

    @Override
    public void getDetails() {
        System.out.println("Type: Triangle");
        System.out.println("Side1: " + side1);
        System.out.println("Side2: " + side2);
        System.out.println("Side3: " + side3);
        System.out.println("Perimeter: " + getPerimeter());
        System.out.println("Area: " + getArea());
    }
}

//Circle.java
public class Circle implements Shape {
    public double PI = Math.PI;
    public int radius;

    public Circle(int radius) {
        this.radius = radius;
    }
    @Override
    public double getPerimeter() {
        return 2 * PI * radius;
    }

    @Override
    public double getArea() {
        return PI * radius * radius;
    }

    @Override
    public void getDetails() {
        System.out.println("Type: Circle");
        System.out.println("Radius: " + radius);
        System.out.println("Perimeter: " + getPerimeter());
        System.out.println("Area: " + getArea());
    }
}

public class Square implements Shape {
    public int side;

    public Square(int side) {
        this.side = side;
    }

    @Override
    public double getPerimeter() {
        return side * 4;
    }

    @Override
    public double getArea() {
        return side * 2;
    }

    @Override
    public void getDetails() {
        System.out.println("Type: Square");
        System.out.println("Side: " + side);
        System.out.println("Perimeter: " + getPerimeter());
        System.out.println("Area: " + getArea());
    }
}

I looked over the getArea() method multiple times and checked for errors.

Put this code

public double s = (side1 + side2 + side3)/2;

into the getArea method.

Currently it is being called before the fields are set.