EXAM: e01: Midterm 1

For this question, you need page 1 of handout A with code for these files: Beverage.java, Edible.java, Food.java, FreeCandy.java and Product.java. These are classes used by a grocery store known as “Trader Bobs”.

Some of these methods will compile and run, while others will not.

Indicate, for each method, whether it compiles or not, and if it does compile, the output when invoked. in context of the classes on handout A and assuming the methods appear inside this class:

public class TraderBobs {
 // methods appear here
}

1. (3 pts)

       public static void TB01 () {
           Beverage b1 = new Beverage(89,"Diet Coke",0,12.0);
           System.out.println("b1: " + b1.getCalories());
       }
   

2. (3 pts)

       public static void TB02 () {
           Product p2 = new Beverage(99,"Coke",150,12.0);
           System.out.println("p2: " + p2.getName());
       }
   

Continued from previous problem…

Some of these methods will compile and run, while others will not.

Indicate, for each method, whether it compiles or not, and if it does compile, the output when invoked. in context of the classes on handout A and assuming the methods appear inside this class:

public class TraderBobs {
 // methods appear here
}

1. (3 pts)

       public static void TB03 () {
   	Product p3 = new Beverage(199,"Milk",130,6.75);
           System.out.println("p3: " + p3.getCalories());
       }
   

2. (3 pts)

       public static void TB04 () {
           FreeCandy f4 = new FreeCandy(25);
           System.out.println("f4: " + f4.getCalories());
       }
   

3. (3 pts)

       public static void TB05 () {
           Edible e5 = new FreeCandy(10);
           System.out.println("e5: " + e5.getCalories());
       }
   

4. (3 pts)

       public static void TB06 () {
           Edible e6 = new Edible(){
   		public int getCalories(){return 50;}
   	    };
           System.out.println("e6: " + e6.getCalories());
       }
   

Continued from previous problem…

Some of these methods will compile and run, while others will not.

Indicate, for each method, whether it compiles or not, and if it does compile, the output when invoked. in context of the classes on handout A and assuming the methods appear inside this class:

public class TraderBobs {
 // methods appear here
}

1. (3 pts)

       public static void TB07 () {
           Food f7 = new Food(99,"Almonds",100,0.63);
           System.out.println("f7: " + f7.getName());
       }
   

2. (3 pts)

       public static void TB08 () {
           Edible e8 = new Food(249,"Kind Bar",200,1.4);
           System.out.println("e8: " + e8.getName());
       }
   

3. (3 pts)

       public static void TB09 () {
           Food f9 = new Food(199,"Gummi Bears",520,5);
           System.out.println("f9: " + f9.getPrice());
       }
   

4. (3 pts)

       public static void TB10 () {
           Product p10 = new Product(299,"Ziploc Bags");
           System.out.println("p10: " + p10.getPrice());
       }
   

(10 pts) Refer to the code for the class Dog with a main that creates some Dog objects.

Your job: figure out after which line of main() each of the following Dog objects is eligible for garbage collection.

If an object is still not eligible for garbage collection when the last line of main is reached, write “never”. Each answer should be a line number, or the word never.

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public class Dog {
    
    private static Dog bestInShow = null;
    private String name;
    
    public static void setBestInShow(Dog b) {
	bestInShow = b;
    }
    
    public static Dog getBestInShow() {
	return bestInShow;
    }
    
    public Dog(String name) { this.name = name;}
    
    public static void main(String [] args) {
	
	Dog d1 = new Dog("Fido");
    	Dog d2 = new Dog("Ginger");
	Dog d3 = new Dog("Harry");
	Dog d4 = new Dog("Izzy");
	Dog d5 = new Dog("Jack");
	Dog d6 = d1;
	
	setBestInShow(d3);   
	d1 = d4;             
	d3 = d6;             
	d1 = null;           
	d2 = null;           
	d3 = null;           
	d4 = null;           
	d5 = null;           
	d6 = null;           
	setBestInShow(null);
    }
}

Given the following program below, determine whether each line of code involves boxing or unboxing, and check the boxes accordingly.

If a line of code involves both, check both boxes. If it involves neither, check neither box.

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import java.util.ArrayList;
public class BoxUnbox {
    public static void main(String [] args) {
	ArrayList<Integer> mylist = new ArrayList<Integer>();
	mylist.add(new Integer(2));
	mylist.add(1);
	mylist.set(0,3);
	int a = mylist.get(0) + mylist.get(1);
	mylist.add(7);
	Integer b = mylist.get(2);
	Integer c = b;
	Integer d = a + c;
	System.out.println("a=" + a + " b= " + b + " c=" + c + " d=" + d);
    }
}

1. (4 pts) If we hire you, the team you'll be working on is trying to work towards increasing the test-case coverage for the source code of company's products. I want to make sure you understand that that means. What does it mean to work towards increased test-case coverage?
2. (6 pts) I also want to make sure you understand the importance of the task. What are some of the benefits of increased test-case coverage for it's code?