Review Questions

Which statements are true?

Select the two correct answers.

Given the following classes and declarations, which statements are true?

// Classes
class Foo {
    private int i;
    public void f() { /* ... */ }
    public void g() { /* ... */ }
}

class Bar extends Foo {
    public int j;
    public void g() { /* ... */ }
}

// Declarations:
// ...
    Foo a = new Foo();
    Bar b = new Bar();
// ...

Select the three correct answers.

Which statement is true?

Select the one correct answer.

Given classes A, B, and C, where B extends A, and C extends B, and where all classes implement the instance method void doIt(). How can the doIt() method in A be called from an instance method in C?

Select the one correct answer.

What would be the result of attempting to compile and run the following code?

// Filename: MyClass.java
public class MyClass {
    public static void main(String[] args) {
        C c = new C();
        System.out.println(c.max(13, 29));
    }
}

class A {
    int max(int x, int y) { if (x>y) return x; else return y; }
}

class B extends A{
    int max(int x, int y) { return super.max(y, x) - 10; }
}

class C extends B {
    int max(int x, int y) { return super.max(x+10, y+10); }
}

Select the one correct answer.

Given the following code, which is the simplest print statement that can be inserted into the print() method?

// Filename: MyClass.java
public class MyClass extends MySuperclass {
    public static void main(String[] args) {
        MyClass object = new MyClass();
        object.print();
    }
    public void print() {
        // INSERT CODE HERE THAT WILL PRINT
        // THE "Hello, world!" STRING FROM THE Message
        // CLASS.
    }
}

class MySuperclass {
    Message msg = new Message();
}

class Message {
    // The message that should be printed:
    String text = "Hello, world!";
}

Select the one correct answer.