1: Quizzes

Question 1

What is the correct method signature for the ‘main’ method used to allow a Java class to serve as a stand-along program?

Answer 1

public static void main(String[] args)

Question 2

When you compile a java program, what is produced?

Answer 2

Object code, which is also called bytecode. (.class file)

Question 3

When you compile a java program, what kind of file is produced?

Answer 3

A .class file.

Question 4

All java programming language statements must end with what?

Answer 4

A semicolon ;

Question 5

You have just written a program that compiles and runs without showing any error messages. However, it does not produce the correct results. What kind of error do you have?

Answer 5

A logic error.

Question 6

What is the mechanism used in the second line of code below that allows a programmer to force a potentially unsafe conversion between data types?

double size = 4.67;
int s = (int)size;

Answer 6

A cast

Question 7

Name 10 Java keywords

Answer 7

public, class, static, void, boolean, char, double, else, final, float, for, if, import, int, long, new, package, private, return, short, throw, throws, while

Question 8

What type of characters are used to define the beginning and end of a Java block, such as a class or method definition?

Answer 8

Curly braces { }

Question 9

Name three important characteristics of a class name.

Answer 9

1. For good style, it should be capitalized.
2. It must match the name of the file where it is stored.
3. It must be one word (no spaces).

Question 10

The process of breaking a large programming task down into a series of smaller ones is called…

Answer 10

Procedural decomposition.

Question 11

The process of breaking a large programming task down into a series of smaller ones is called…

Answer 11

Procedural decomposition.

Question 12

What is the correct syntax for a method header with parameters?

Answer 12

public static int example(int x, int y) {

Question 13

What is the term when you have 2 methods in a class with the same name, but different parameter lists?

Answer 13

Method overloading

Question 14

What is the keyword used to indicate that a method returns no value?

Answer 14

void

Question 15

What is the name of the package that contains Scanner?

Answer 15

java.util

Question 16

When you want to call a method on an object, in other words - send the object a message - what is the proper syntax?

Answer 16

objectName.methodName()

Question 17

Name the different data types that represent integer values (from smallest to largest).

Answer 17

byte, short, int, long

Question 18

Name the different data types that represent floating point numbers (from smallest to largest).

Answer 18

float, double

Question 19

Name the eight primitive data types.

Answer 19

byte, short, int, long, float, double, char, boolean

Question 20

What is a binary operator?

Answer 20

Any operator that takes two operands.

Question 21

What’s the name of an expression where the binary operator has two operands of different data types?

Answer 21

Mixed-type expression.

Question 22

Even though widening is legal from type long to type float, what can happen?

Answer 22

Widening from type long to type float is legal, because the range of possible float values includes the range of all possible long values. However, some loss of precision is possible in such a conversion because a long value can have as many as 19 significant figures, whereas a float is limited to about 7.

Question 23

Rank the primitive data types from narrowest to widest.

Answer 23

boolean (true/false) & byte (integer) –> char (characters) & short (integer) –> int (integer) –> long (integer) –> float (floating point numbers) –> double (floating point numbers)

Question 24

“The scope of this type of variable begins with its declaration inside a method and ends at the end of the block in which it is declared.” What kind of variable is it?

Answer 24

Local variable

Question 25

Which of the following statements are true?

1. A method may have no parameters.
2. A method may have one or more parameters.
3. A method may or may not return a value.

Answer 25

All 3 are true.

Question 26

Which of the following is the name of a reference type (object type) we have encountered this quarter?

String
Graphics
Scanner
DrawingPanel

Answer 26

All of them.

Question 27

The arguments of a method call must match the parameters of a method definition in what ways?

Answer 27

1. The number of arguments must match the number of parameters
2. The order in which the arguments are listed must match the parameters
3. The data type of each argument must match the corresponding parameter

Question 28

What units are required when specifying an angle for the trigonometric methods (sin, cos, etc.)?

Answer 28

Radians

Question 29

If two methods within the same class have the same name and different parameter lists, what do you have?

Answer 29

An overloaded method.

Question 30

What is the name given to a method that can be called using the name of its class, rather than an object reference, as a qualifier (for example, Math.round(…))?

Answer 30

A class method or static method.

Question 31

Which of the following is NOT true about class Scanner?

1. The Scanner class is part of the java.util package.
2. A Scanner object can be used to get keyboard input if it is constructed using System.in as the source stream.
3. A Scanner object must be constructed before it can be used.
4. All of the Scanner methods return type String.
5. None of the above – all of these statements are true.

Answer 31

4. All of the Scanner methods return type String.

Question 32

What is the correct syntax for declaring a class constant named BET_LIMIT?

Answer 32

public static final int BET_LIMIT = 1000;

Question 33

What is the proper way to instantiate a DrawingPanel object?

Answer 33

DrawingPanel dp = new DrawingPanel(500, 500);

Question 34

What is the name of a post-test loop in Java, meaning that its test is at the bottom?

Answer 34

do…while

Question 35

A problem type known as “loop and a half” is solved using what type of loop?

Answer 35

fencepost