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Strategy 3

  1. The E3 interface has a void pickle() method and a int gc() method. Write the complete E3 interface.

  2. There is nothing to do in this question, it just shows the TestStuff message. All of your demo methods should go in this class.

public class TestStuff {
   public static void tester(E3 v) {
        System.out.println(v.gc());
        System.out.println(v.gc());
        v.pickle();
        System.out.println(v.gc());
        v.pickle();
        System.out.println(v.gc());
    }
}
  1. The E3A class implements the E3 interface. Make it behave according to the demo code below. You will need to write a constructor and some methods.
    public static void demoA() {
        E3A x = new E3A(5);
        tester(x); // prints 5 5 7 9
    }
}
  1. The E3B class implements the E3 interface. Add the demoB method to the TestStuff class and make your E3B class behave as described.
public static void demoB() {
    E3B y = new E3B (3,7);
    tester(y); // prints 21, 21, 35, 49
    E3B z = new E3B (3,10);
    tester(z); // prints 30, 30, 50, 70
    E3B w = new E3B (5,10);
    tester(w); // prints 50, 50, 70, 90
}
  1. The E3C class is a subclass of E3B. Add the demoC method to TestStuff and implement the E3C class.
public static void demoC() {
    E3C y = new E3C (3,7);
    tester(y); // prints 21, 21, 21, 21
    E3C z = new E3C (5,10);
    tester(z); // prints 50, 50, 50, 50
}
  1. The code below is placed in the TestStuff class. Without it, write the predicted result from each line. If the given line is an error, indicate that and ignore the line.
public static E3 bOnly(E3B w) {
    w.gc();
    return w;
}

public static void demoD() {
    E3B m = new E3B(4,5);   // line 1
    E3B p = new E3C(-2,30); // line 2

    E3 x;
    x = bOnly(m); // line 3
    tester(x);    // line 4
    x = bOnly(p); // line 5
    tester(x);    // line 6
}
  1. Does this work? Explain precisely why or why not. Fix if possible.
public static void demoE() {
    E3B n = new E3A(20);
    E3B x = bOnly(n);
    tester(x);
}