Prepare for Java Exam 1

What will be the values of ans, x, and y after the following statements are executed? int ans = 35, x = 50, y = 50; if (x >= y) { ans = x + 10;x -= y; } else { ans = y + 10;y += x; }

ans = 60, x = 0, y = 50

Mistyping println as printn will result in

a syntax error

Which of the following will yield a pseudorandom number in the range of 10 and 15 inclusive (The range includes both 10 and 15), given: Random gen = new Random();

10 + gen.nextInt(6)

What will be displayed after the following statements are executed? int ans = 10; int x = 65; int y = 55; if (x >= y) { int ans = x + y; } System.out.println(ans);

120

What characters does NOT need to have an associated closing character in a Java program?

<

What happens if you attempt to use a variable before it has been initialized?

A syntax error may be generated by the compiler, and a run-time error may occur during execution.

Java.text's NumberFormat class includes methods that

Allow you to format percentages, round their display during the formatting process and allow you to format currency

True or false When two strings are compared using the String class's compareTo method, the comparison is not case sensitive.

False

True or false: Programs never need more than one path of execution.

False

True or false: All it takes for an OR expression to be true is for one of the subexpressions to be true.

False

True or false: The values of (double)5/2 and (double)(5/2) are identical.

False

True or false: These two ways to set up a String will yield identical results: String my_string = "12345"; String my_string = 12345;

False

True or false: When testing for character values, the switch statement does not test for the case of the character.

False

True or false: In Java the variable named total is the same as the variable named Total.

False

True or false: You may use the Str.replace('b', 'n') method to remove characters from a String.

False

What is NOT a rule that must be followed when naming identifiers?

Identifiers can contain spaces.

What is the function of the dot operator?

It allows one to access the data within an object when given a reference to the object, and It allows one to invoke a method within an object when given a reference to the object.

What is TRUE regarding the remainder operator, %?

It can be performed on any numeric values and its result is always numeric.

The advantages of the DecimalFormat class compared to the NumberFormat class include

Precise control over the number of digits to be displayed and control's over the presence of a leading zero

________ operators are used to determine whether a specific relationship exists between two values.

Relational

An alias is when

two different reference variables refer to the same physical object

In Java, ________ must be declared before they can be use

variables

In Java, instantiation means

creating a new object of the class

Using Java naming convention, what would be a good variable name for the current value of a stock?

currentStockVal

A ________ is a boolean variable that signals when some condition exists in the program.

flag

It is important to dissect a problem into manageable pieces before trying to solve the problem because

most problems are too complex to be solved as a single, large activity

The switch statement is a ________.

multiple alternative decision structure

This is a variable whose content is read only and cannot be changed during the program's execution.

named constant

What does the following line of Java code do? //System.out.println("Hello");

nothing

Character literals are enclosed in ________; string literals are enclosed in ________.

single quotes; double quotes

What would require an explicit typecast?

storing a float in an int

If str1 and str2 are both String objects, which of the following expressions will correctly determine whether or not they are equal?

str1.equals(str2)

The word println is a(n)

method

Which of the following is the not equal operator?

!=

What is the value of z after the following assignment statement is executed? double z = 5/10;

0.5

What will be the value of bonus after the following statements are executed? int bonus, sales = 10000; if (sales < 5000) bonus = 200; else if (sales < 7500) bonus = 500; else if (sales < 10000) bonus = 750; else if (sales < 20000) bonus = 1000; else bonus = 1250;

1000

Assume that x and y are ints equal to 10 and 5 respectively. What is the output of the following statement? System.out.println("" + x + y);

105

Enclosing a group of statements inside a set of braces creates

a block of statements.

What is TRUE regarding Java syntax and semantics?

A Java compiler can determine if you have followed proper syntax but not proper semantics

What comment might be added to explain the following instruction? System.out.println("Hello World");

Demonstrate an output message

Java is a strongly typed language. What is meant by "strongly typed"?

Every variable has a single type associated with it throughout its existence in the program and the variable can only store values of that type.

What is NOT true regarding Java as a programming language?

Java is a language whose programs do not require translating into machine language before they are executed.

What cannot be used as identifiers in Java?

Key words

________ works like this: If the expression on the left side of the && operator is false, the expression the right side will not be checked.

Short-circuit evaluation

When the + operator is used with strings, it is known as the:

String concatenation operator

Consider the following programimport. java.util.Scanner; public class Questions33_34 { public static void main(String[] args) { int x, y, z; double average; Scanner scan = new Scanner(System.in); System.out.println("Enter an integer value"); x = scan.nextInt(); System.out.println("Enter another integer value"); y = scan.nextInt(); System.out.println("Enter a third integer value"); z = scan.nextInt(); average = (x + y + z) / 3; System.out.println("The result of my calculation is " + average); } } Is this code computing the correct average?

The average of x, y, and z as a double but the result may not be accurate

Assume you write a program that uses the Random class but you fail to include an import statement for java.util.Random or java.util.*. What will happen when you attempt to compile and run your program?

The program won't compile and you'll receive a syntax error about the missing class.

In an if-else statement, if the boolean expression is false then ________.

The statement or block following the else is executed

If the following Java statements are executed, what will be displayed? System.out.println("The top three winners are\n"); System.out.print("Jody, the Giant\n"); System.out.print("Buffy, the Barbarian"); System.out.println("Adelle, the Alligator");

The top three winners are Jody, the GiantBuffy, the BarbarianAdelle, the Alligator

What properties are TRUE of String objects?

Their length never changes and the shortest String has zero length.

True or false: All the methods in the Math class are declared to be static.

True

True or false: There are three ways that data conversion may occur: by assignment, by promotion, and by casting.

True

True or false: A variable's scope is the part of the program that has access to the variable.

True

True or false: All it takes for an OR expression to be true is for one of the subexpressions to be true.

True

True or false: In a switch statement, each of the case values must be unique.

True

To display the output on the next line, you can use the println method or use this escape sequence in the print method.

\n

Which character is NOT allowed in an identifier?

^

Comments should

be insightful and explain the intention of an instruction or block of code

Which of the following expressions determines whether the char variable, chrA, is not equal to the letter 'A'?

chrA != 'A'

Variables are classified according to their:

data type

Variables of the boolean data type are useful for:

evaluating true/false conditions

What is a legal Java programmer's defined identifier?

i

What determines whether the variable temp is within the range of 0 through 100 (inclusive)?

if (temp >= 0 && temp <= 100)

An error in a program that results in the program outputting $100 instead of the correct answer, $250, is a

logical error

What is a legal Java identifier?

oneForAll

The main method for a Java program is defined by

public static void main(String[] args)

What is NOT syntactically legal in Java?

s t a t i c main(String[] args)

Given the following two lines of code, what can be said about s1 and s2? String s1 = "testing" + " 123"; String s2 = new String("testing 123");

s1 and s2 are references to different String objects.

The String class's compareTo method

yields 0 if the two strings are identical