请用接口实现以下UML图 ，Java程序：测试类中，有三个柱体，分别以三角形，圆形，矩形为底面积，求它们的体积。 测试用例：:三角形边：（3，4，5）;圆形半径：2; 矩形边（3，4），柱体高：6.

以下是Java程序的实现，其中定义了Geometry接口和Circle、Triangle、Rectangle三个类来实现UML图中的三个形状，最后在Test类中计算柱体的体积：

interface Geometry {
    double getArea();
}

class Circle implements Geometry {
    private double radius;

    public Circle(double radius) {
        this.radius = radius;
    }

    public double getArea() {
        return Math.PI * radius * radius;
    }
}

class Triangle implements Geometry {
    private double a, b, c;

    public Triangle(double a, double b, double c) {
        this.a = a;
        this.b = b;
        this.c = c;
    }

    public double getArea() {
        double p = (a + b + c) / 2;
        return Math.sqrt(p * (p - a) * (p - b) * (p - c));
    }
}

class Rectangle implements Geometry {
    private double length, width;

    public Rectangle(double length, double width) {
        this.length = length;
        this.width = width;
    }

    public double getArea() {
        return length * width;
    }
}

public class Test {
    public static void main(String[] args) {
        Circle circle = new Circle(2);
        Triangle triangle = new Triangle(3, 4, 5);
        Rectangle rectangle = new Rectangle(3, 4);
        double height = 6;

        double volume1 = circle.getArea() * height;
        double volume2 = triangle.getArea() * height;
        double volume3 = rectangle.getArea() * height;

        System.out.println("圆柱体体积：" + volume1);
        System.out.println("三角柱体体积：" + volume2);
        System.out.println("矩形柱体体积：" + volume3);
    }
}

输出结果为：

圆柱体体积：75.39822368615503
三角柱体体积：36.0
矩形柱体体积：72.0