JAVA Revision Lecture

Electronic Voting System

Marina De Vos

0a. What are the languages used in this unit?

1 2 3

0%8%

92%1. C and Java

2. Python and Java

3. Perl and VisualBasic

0b. Ada Lovelace was the first …

1 2 3

48%

39%

13%

1. female programmer

2. the wife of the first programmer

3. programmer

1. Which one of the sentences is true considering the following lines

of code:

1 2 3

71%

13%17%

String country = "England";Town bath = new Town(country);

1. the class Town contains a constructor with a String as a parameter

2. bath is an instance of the class England

3. bath is an object of type String

2. What is the value returned while calling the method refundBalance(10)?

1 2 3 4

4%8%

80%

8%

public int refundBalance(int nb){ balance=100; return balance; balance=0;}

1. 0

2. 10

3. 100

4. Same value as before

3. Which one of the following sentences is correct?

1 2 3 4 5

23%

50%

4%8%

15%

1. Fields represent local variables of a method

2. The scope of a local variable is linked to its defining method

3. Fields are defined inside constructors

4. Local variables are defined in the header of a method

5. A private field can be accessed from outside their

defining class

4. Which values have the variables a and b after the execution of the

following lines of code:

1 2 3 4 5

4%

23%

58%

12%

4%

int a=3;int b=5;int c=a++;int d=--b;if ((a+1)==d){ c++; b--;}if (c!=b){ a++;}else { b++;}

1. a=3; b=4;

2. a=4; b=4;

3. a=3; b=5;

4. a=5; b=4;

5. a=4; b=5;

5. What is the result of n?

1 2 3

24%

44%

32%

boolean pass=false; int n=0; for (int i=0; i<10; i++) { n+=i; if (pass) { i+=2; } pass = !pass; }

1. 27

2. 25

3. 45

6. Why do you need to add 'throws' to a method signature...

1 2 3 4

35%

23%

19%

23%

1. To Specify the exceptions thrown by a method

2. To specify the exceptions caught by a method

3. To Specify that a method overrides an exception

4. Both 1 and 2 are correct Choice One

7. A 'try' must be followed by one or more 'catch' blocks.

1 2

19%

81%

1. True

2. False

8. What happens to the object being created when an exception is thrown from a constructor?

1 2 3 4

62%

4%

27%

8%

1. null is returned and the partial object is garbage collected

2. a partial object is created

3. null is returned4. the object is fully

created

9. Code that is well designed is:

1 2 3 4

12%

62%

15%12%

1. tighly coupled and not cohesive

2. loosly coupled and not cohesive

3. tighly coupled and highly cohesive

4. loosly coupled and highly cohesive

10. Java is a …

1 2 3 4

8%

40%44%

8%

1. weakly and statically typed language

2. weakly and dynamically typed language

3. strongly and statically typed language

4. strongly and dynamically typed language

11. The lifetime and scope of a variable a is defined by the

enclosing {} braces.

1 2

56%

44%

1. True

2. False

12. Object diagrams can present both a static and dynamic view of a

program.

1 2

62%

38%

1. True

2. False

13. To create a new primitive type in Java, you can...

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8%

19%

12%

62%

1. copy an existing primitive type definition and edit

2. ...you can't!

3. use the new primitive keyword

4. not necessary - all new types are primitive types

14. A & B is the same as B & A for any boolean expression in Java.

1 2

64%

36%

1. True

2. False

15. In Java, it is not possible to have more than one method with

the same name.

1 2

67%

33%

1. True

2. False

16. Consider the following code snippet: What will the output be?

1 2 3 4

8%

40%

32%

20%

HashMap<String,String> map = new HashMap<String,String>(); map.put("key1","arr"); map.put("key1","matey"); System.out.println(map.get("key1"));

1. arr

2. Nothing, it will generate an error.

3. arr matey

4. matey

17. Which of the following statements is incorrect?

1 2 3 4

24%

36%

20%20%

1. the static type of a variable is either the same as the dynamic type or a superclass

2. polymorphic method calls use the dynamic type

3. The compiler checks the static and dynamic type of a variable

4. an object reference can always be type cast back to its dynamic type

18 Newly declared methods can hide, implement, or override methods declared in

a superclass or superinterface.

1 2

36%

64%1. True

2. False

19 It is possible to have a variable with a static type corresponding to an abstract

class

1 2

46%

54%1. True

2. False

20 To simulate multiple inheritance you use:

1 2 3 4

19%

31%

35%

15%

1. nested classes

2. abstract classes

3. interfaces

4. inherited classes

EVS is good fun, something different and its very good to be interactive

Since we do not get much class participation, except if we want to ask questions

1 2 3 4 5

68%

8%12%

0%

12%

1. Strongly Agree

2. Agree

3. Neutral

4. Disagree

5. Strongly Disagree

Java EVS vs Python Quiz

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44%

4%

24%28%

1. evs

2. Quiz

3. I liked both

4. I liked neither

EVS: Although good for general feed-back how we are doing, it’s not so good for passing course

material on.

1 2 3 4 5

0% 0% 0%0%0%

1. Strongly Agree

2. Agree

3. Neutral

4. Disagree

5. Strongly Disagree