my area is not getting printed (abstract using interface)

Question

I am currently new to interfaces and I encountered this problem regarding my getArea(), I would love if you guys can point out the error on my code

while this is my Triangle abstract class, I am not sure whether I putted the Semi-perimeter(sp) right or not:

    private int sideA;
    private int sideB;
    private int sideC;

    int sp = (sideA+sideB+sideC)/2;
    double area = Math.sqrt(sp*(sp-sideA)*(sp-sideB)*(sp-sideC));
    
    public Triangle() {
        
    }
    public Triangle(int sideA, int sideB, int sideC, int sp, double area) {
        this.sideA=sideA;
        this.sideB=sideB;
        this.sideC=sideC;   
        
    }

    public int getSideA() {
        return sideA;
    }

    public void setSideA(int sideA) {
        this.sideA = sideA;
    }

    public int getSideB() {
        return sideB;
    }

    public void setSideB(int sideB) {
        this.sideB = sideB;
    }

    public int getSideC() {
        return sideC;
    }

    public void setSideC(int sideC) {
        this.sideC = sideC;
        
    }
    
    public double getPerimeter() {
        return sideA+sideB+sideC;
    }

    public double getArea() {
        return getArea();
    }

    public void getDetails() {
        System.out.println("\nType: Triangle" + "\nSides: " +this.sideA +", " +this.sideB+", "+this.sideC + "\nPerimeter: "
                + getPerimeter() + "\nArea: " + getArea() + "\ns: "+sp);
    }
}```