RoachPopulation.java

public class RoachPopulation {
    private static double initialPopulation;

    RoachPopulation(double initialPopulation) {
        this.initialPopulation = initialPopulation;
    }

    public void waitForIt() {
        initialPopulation *= 2.0;
    }

    public void splay() {
        initialPopulation *= 0.9;
    }

    public void print() {
        System.out.println("There are " + Double.toString(initialPopulation));
    }

    public static void main(String[] args) {
        RoachPopulation roachPop = new RoachPopulation(12.0);
        roachPop.print();
        roachPop.waitForIt();
        roachPop.print();
        roachPop.waitForIt();
        roachPop.print();
        roachPop.waitForIt();
        roachPop.print();
        roachPop.splay();
        roachPop.print();
    }
}