Question 1
Question
To add a value 1 to variable x, you write (Choose all that apply.)
Answer
-
x += 1;
-
x = 1 + x;
-
x := 1;
-
x = x + 1;
-
1 + x = x;
Question 2
Question
An overloaded method is one that
Answer
-
has a different name than another method, but the same parameters.
-
has the same name as another method, but different parameters (by number, types or order of the types).
-
has the same name and parameters as a method defined in another class.
-
has the same name and parameters, but a different return type as another method.
Question 3
Question
In Java, the word true is ________.
Answer
-
same as value 0
-
same as value 1
-
a Boolean literal
-
a Java keyword
Question 4
Question
The ________ method parses a string s to a double value.
Answer
-
double.parseDouble(s);
-
double.parse(s);
-
Double.parsedouble(s);
-
Double.parseDouble(s);
Question 5
Question
Suppose variable gender is MALE and age equals 60, how is the expression
( gender == FEMALE ) && ( age >= 65 )
evaluated?
Answer
-
The condition ( gender == FEMALE ) is evaluated first and the evaluation stops immediately.
-
The condition ( age >= 65 ) is evaluated first and the evaluation stops immediately.
-
Both conditions are evaluated, from left to right.
-
Both conditions are evaluated, from right to left.
Question 6
Question
Will the following program terminate?
int balance = 10;
while (true) {
if (balance < 9) continue;
balance = balance - 9;
}
Question 7
Question
What is the output of the following code?
boolean even = false;
System.out.println((even ? "true" : "false"));
Answer
-
true
-
true false
-
false
-
nothing
Question 8
Question
Which command compiles the Java source code file Welcome.java?
Answer
-
cd Welcome.java
-
javac Welcome.java
-
java Welcome.java
-
compile Welcome.java
Question 9
Question
The following code fragment reads in two numbers: (Choose all that apply.)
Scanner input = new Scanner(System.in);
int i = input.nextInt();
double d = input.nextDouble();
What are the correct ways to enter these two numbers?
Answer
-
Enter an integer, an Enter key, a double value, and then the Enter key.
-
Enter an integer, a space, a double value, and then the Enter key.
-
Enter an integer, two spaces, a double value, and then the Enter key.
-
Enter a numeric value with a decimal point, a space, an integer, and then the Enter key.
Question 10
Question
Suppose s1 and s2 are two strings. Which of the following statements or expressions is incorrect? (Choose all that apply.)
Question 11
Question
Which statement is true?
Answer
-
A while statement cannot be nested inside another while statement.
-
An if statement cannot be nested inside another if statement.
-
A while statement cannot be nested inside an if statement.
-
None of the above is true.
Question 12
Question
What is output by the following Java code segment?
int temp;
temp = 180;
while ( temp != 80 )
{
if ( temp > 90 )
{
System.out.print( "This porridge is too hot! " );
// cool down
temp = temp – ( temp > 150 ? 100 : 20 );
} // end if
else
{
if ( temp < 70 )
{
System.out.print(
"This porridge is too cold! ");
// warm up
temp = temp + (temp < 50 ? 30 : 20);
} // end if
} // end else
} // end while
if ( temp == 80 )
System.out.println( "This porridge is just right!" );
Answer
-
This porridge is too cold! This porridge is just right!
-
This porridge is too hot! This porridge is just right!
-
This porridge is just right!
-
None of the above.
Question 13
Question
Suppose s is a string with the value "java". What will be assigned to x if you execute the following code?
char x = s.charAt(4);
Question 14
Question
Which of these statements best defines scope?
Answer
-
Scope refers to the classes that have access to a variable.
-
Scope determines whether a variable's value can be altered.
-
Scoping allows the programmer to use a class without using its fully qualified name.
-
Scope is the portion of a program that can refer to an entity by its simple name.
Question 15
Question
What is the value of (double)5/2?
Question 16
Question
What does the expression x %= 10 do?
Answer
-
Adds 10 to the value of x, and stores the result in x.
-
Divides x by 10 and stores the remainder in x.
-
Divides x by 10 and stores the integer result in x.
-
None of the above.
Question 17
Question
Which of the following is not a package in the Java API?
Answer
-
java.characters.
-
java.awt.
-
javax.swing.event.
-
java.lang.
Question 18
Question
Suppose x=10 and y=10 what is x after evaluating the expression (y >= 10) || (x-- > 10)?
Question 19
Question
Each time a method is invoked, the system stores parameters and local variables in an area of memory, known as ________, which stores elements in last-in first-out fashion.
Answer
-
a stack
-
an array
-
a heap
-
storage area
Question 20
Question
Counter-controlled repetition requires
Answer
-
A control variable and initial value.
-
A control variable increment (or decrement).
-
A condition that tests for the final value of the control variable.
-
All of the above.
Question 21
Question
Which of the following assignment statements is correct? (Choose all that apply.)
Answer
-
char c = 'd';
-
char c = "100";
-
char c = "d";
-
char c = 100;
Question 22
Question
To add 0.01 + 0.02 + ... + 1.00, what order should you use to add the numbers to get better accuracy?
Answer
-
add 1.00, 0.99, 0.98, ..., 0.02, 0.01 in this order to a sum variable whose initial value is 0.
-
add 0.01, 0.02, ..., 1.00 in this order to a sum variable whose initial value is 0.
Question 23
Question
(int)(Math.random() * (65535 + 1)) returns a random number ________.
Answer
-
between 1 and 65535
-
between 0 and 65536
-
between 0 and 65535
-
between 1 and 65536
Question 24
Question
What is the return value of "SELECT".substring(4, 4)?
Question 25
Question
What is the value of (double)(5/2)?
Question 26
Question
Which of the following statements will print a single line containing "hello there"?
Answer
-
System.out.println( "hello" );
System.out.println( " there" );
-
System.out.println( "hello" , " there" );
-
System.out.println( "hello" );
System.out.print( " there" );
-
System.out.print( "hello" );
System.out.println( " there" );
Question 27
Question
Which of the following operators are right-associative?
Question 28
Question
What is displayed on the console when running the following program?
class Test {
public static void main (String[ ] args) {
try {
System.out.println("Welcome to Java");
}
finally {
System.out.println("The finally clause is executed");
}
}
}
Question 29
Question
Which of the following exceptions is a checked exception?
Answer
-
ArithmeticException.
-
IOException.
-
InputMismatchException.
-
RuntimeException.
Question 30
Question
What exception type does the following program throw?
public class Test {
public static void main(String[ ] args) {
System.out.println(1 / 0);
}
}
Question 31
Question
What is wrong in the following program?
class Test {
public static void main (String[ ] args) {
try {
System.out.println("Welcome to Java");
}
}
}
Answer
-
You cannot have a try block without a catch block.
-
A method call that does not declare exceptions cannot be placed inside a try block.
-
You cannot have a try block without a catch block or a finally block.
-
Nothing is wrong.
Question 32
Question
Which of the following statements is true?
Answer
-
The new exception class should extend RuntimeException if the program should be required to handle the exception.
-
Using existing exceptions makes the program less robust.
-
Always create your own exception classes.
-
Like any other class, an exception class can contain fields and methods.
Question 33
Question
What is displayed on the console when running the following program?
class Test {
public static void main(String[ ] args) {
try {
System.out.println("Welcome to Java");
int i = 0;
int y = 2/i;
System.out.println("Welcome to HTML");
}
finally {
System.out.println("The finally clause is executed");
}
}
}
Answer
-
The program displays three lines: Welcome to Java, Welcome to HTML, The finally clause is executed.
-
Welcome to Java.
-
None of the above.
-
Welcome to Java followed by The finally clause is executed in the next line.
Question 34
Question
What is the difference between a try block and a try statement?
Answer
-
A try statement refers to the block of code following the keyword try, while the try block refers to the try keyword and the block of code following this keyword.
-
The try statement refers to the keyword try followed by a block of code. The try statement and its corresponding catch and/or finally clauses together form a try block.
-
There is no difference; the terms can be used interchangeably.
-
The try block refers to the keyword try followed by a block of code. The try block and its corresponding catch and/or finally clauses together form a try statement.
Question 35
Question
If the catch-or-declare requirement for a checked exception is not satisfied:
Answer
-
a stack trace will be displayed, along with a message indicating that the exception must be caught.
-
a stack trace will be displayed indicating the exception that has occurred and where it occurred.
-
the compiler will issue an error message indicating that the exception must be caught or declared.
-
the compiler will issue an error message indicating that the exception must be caught.
Question 36
Question
When an exception occurs it is said to have been:
Answer
-
handled.
-
thrown.
-
caught.
-
declared.
Question 37
Question
Exceptions can be thrown by:
Question 38
Question
Analyze the following code:
class Test {
public static void main(String[ ] args)
throws MyException {
System.out.println("Welcome to Java");
}
}
class MyException extends Error {
}
Answer
-
You cannot declare an exception in the main method.
-
You declared an exception in the main method, but you did not throw it.
-
The program has a compilation error.
-
You should not declare a class that extends Error, because Error raises a fatal error that terminates the program.
Question 39
Question
The following code causes Java to throw ________.
int number = Integer.MAX_VALUE + 1;
Answer
-
Error
-
RuntimeException
-
no exceptions
-
Exception
-
Throwable
Question 40
Question
A Java exception is an instance of ________.
Answer
-
RuntimeException
-
Error
-
NumberFormatException
-
Exception
-
Throwable
Question 41
Question
Which of the following statements is true?
Answer
-
The code in a finally block is executed only if an exception occurs.
-
The code in a finally block is executed only if an exception does not occur.
-
None of the above are true.
-
The code in a finally block is executed only if there are no catch blocks.
Question 42
Question
Suppose ArrayList x contains two strings [Beijing, Singapore]. Which of the following method will cause runtime errors? (Choose all that apply.)
Answer
-
x.get(1)
-
x.size()
-
x.remove(2)
-
x.get(2)
-
x.set(2, "New York");
Question 43
Question
Which keyword is used to specify that a class will define the methods of an interface?
Answer
-
implements.
-
extends.
-
defines.
-
uses.
Question 44
Question
A(n) ____________________ class cannot be instantiated.
Answer
-
polymorphic.
-
abstract.
-
concrete.
-
final.
Question 45
Question
Failure to prefix the superclass method name with the keyword super and a dot (.) separator when referencing the superclass's method causes ________.
Answer
-
a syntax error.
-
a compile-time error.
-
a runtime error.
-
infinite recursion.
Question 46
Question
The equals method is defined in the Object class. Which of the following is correct to override it in the String class?
Answer
-
public static boolean equals(String other)
-
public boolean equals(String other)
-
public static boolean equals(Object other)
-
public boolean equals(Object other)
Question 47
Question
Inheritance means ________.
Answer
-
that a variable of supertype can refer to a subtype object
-
that data fields should be declared private
-
that a class can contain another class
-
that a class can extend another class
Question 48
Question
Analyze the following code:
Cylinder cy = new Cylinder(1, 1);
Circle c = cy;
Question 49
Question
Encapsulation means ________.
Answer
-
that a class can extend another class
-
that data fields should be declared private
-
that a variable of supertype can refer to a subtype object
-
that a class can contain another class
Question 50
Question
private fields of a superclass can be accessed in a subclass
Question 51
Question
Suppose ArrayList x contains two strings [Beijing, Singapore]. Which of the following method will cause the list to become [Beijing]? (Choose all that apply.)
Answer
-
x.remove(1)
-
x.remove("Singapore")
-
x.remove(0)
-
x.remove(2)
Question 52
Question
You can assign ________ to a variable of Object[ ] type. (Choose all that apply.)
Answer
-
new java.util.Date[100]
-
new String[100]
-
new double[100]
-
new char[100]
-
new int[100]
Question 53
Question
Which of the following statements are true? (Choose all that apply.)
Answer
-
A private method cannot be overridden. If a method defined in a subclass is private in its superclass, the two methods are completely unrelated.
-
Overloading a method is to provide more than one method with the same name but with different signatures to distinguish them.
-
It is a compilation error if two methods differ only in return type in the same class.
-
To override a method, the method must be defined in the subclass using the same signature and compatible return type as in its superclass.
-
A static method cannot be overridden. If a static method defined in the superclass is redefined in a subclass, the method defined in the superclass is hidden.
Question 54
Question
Given the following code:
class C1 {}
class C2 extends C1 { }
class C3 extends C2 { }
class C4 extends C1 {}
C1 c1 = new C1();
C2 c2 = new C2();
C3 c3 = new C3();
C4 c4 = new C4();
Which of the following expressions evaluates to false?
Answer
-
c4 instanceof C2
-
c1 instanceof C1
-
c3 instanceof C1
-
c2 instanceof C1
Question 55
Question
Object-oriented programming allows you to derive new classes from existing classes. This is called ________.
Answer
-
generalization
-
encapsulation
-
inheritance
-
abstraction
Question 56
Question
What is the printout for the third statement in the main method?
public class Foo {
static int i = 0;
static int j = 0;
public static void main(String[ ] args) {
int i = 2;
int k = 3;
{
int j = 3;
System.out.println("i + j is " + i + j);
}
k = i + j;
System.out.println("k is " + k);
System.out.println("j is " + j);
}
}
Answer
-
j is 3
-
j is 1
-
j is 2
-
j is 0
Question 57
Question
The UML represents operations by listing the operation name, followed by a ________-separated list of parameters in parentheses, a ________ and the return type.
Answer
-
comma, colon.
-
colon, semicolon.
-
colon, colon.
-
comma, semicolon.
Question 58
Question
Analyze the following code:
class Circle {
private double radius;
public Circle(double radius) {
radius = radius;
}
}
Answer
-
The program will compile, but you cannot create an object of Circle with a specified radius. The object will always have radius 0.
-
The program has a compilation error because you cannot assign radius to radius.
-
The program does not compile because Circle does not have a default constructor.
-
The program has a compilation error because it does not have a main method.
Question 59
Question
Which diagram models system structure?
Answer
-
State machine diagram.
-
Activity diagram.
-
Class diagram.
-
Sequence diagram.
Question 60
Question
Which of the following is the first stage of the software life cycle?
Answer
-
testing.
-
implementation.
-
requirements gathering.
-
design.
Question 61
Question
Analyze the following code.
public class Test {
int x;
public Test(String t) {
System.out.println("Test");
}
public static void main(String[ ] args) {
Test test = new Test();
System.out.println(test.x);
}
}
Answer
-
The program has a compile error because System.out.println method cannot be invoked from the constructor.
-
The program has a compile error because Test does not have a default constructor.
-
The program has a compile error because you cannot create an object from the class that defines the object.
-
The program has a compile error because x has not been initialized.
Question 62
Question
Analyze the following code.
public class Test {
int x;
public Test(String t) {
System.out.println("Test");
}
public static void main(String[ ] args) {
Test test = null;
System.out.println(test.x);
}
}
Answer
-
The program has a compile error because you cannot create an object from the class that defines the object.
-
The program has a compile error because x has not been initialized.
-
The program has a compile error because test is not initialized.
-
The program has a runtime NullPointerException because test is null while executing test.x.
-
The program has a compile error because Test does not have a default constructor.
Question 63
Question
Assume java.util.Date[ ] dates = new java.util.Date[10], which of the following statements are true? (Choose all that apply.)
Answer
-
dates is null.
-
dates = new Date() is fine, which creates a new Date object and assigns to dates.
-
dates = new java.util.Date[5] is fine, which assigns a new array to dates.
-
dates[0] is null.
Question 64
Question
The java.util.Date class is introduced in this section. Which of the following code creates an object of the Date class? (Choose all that apply.)
A:
public class Test {
public Test() {
new java.util.Date();
}
}
B:
public class Test {
public Test() {
java.util.Date date = new java.util.Date();
}
}
Question 65
Question
________ is a construct that defines objects of the same type.
Answer
-
A class
-
A method
-
A data field
-
An object
Question 66
Question
Which two Java primitive types store floating-point numbers?
Answer
-
decimal and float.
-
point and double.
-
decimal and point.
-
float and double.
Question 67
Question
What is the printout of the second println statement in the main method?
public class Foo {
int i;
static int s;
public static void main(String[ ] args) {
Foo f1 = new Foo();
System.out.println("f1.i is " + f1.i + " f1.s is " + f1.s);
Foo f2 = new Foo();
System.out.println("f2.i is " + f2.i + " f2.s is " + f2.s);
Foo f3 = new Foo();
System.out.println("f3.i is " + f3.i + " f3.s is " + f3.s);
}
public Foo() {
i++;
s++;
}
}
Answer
-
f2.i is 2 f2.s is 2
-
f2.i is 1 f2.s is 2
-
f2.i is 2 f2.s is 1
-
f2.i is 1 f2.s is 1
Question 68
Question
Which of the following statements are true? (Choose all that apply.)
Answer
-
Constructors are invoked using the new operator when an object is created.
-
At least one constructor must always be defined explicitly.
-
Constructors do not have a return type, not even void.
-
A default no-arg constructor is provided automatically if no constructors are explicitly declared in the class.
-
Constructors must have the same name as the class itself.
Question 69
Question
An object is an instance of a ________.
Answer
-
method
-
program
-
data
-
class
Question 70
Question
When you pass an array to a method, the method receives ________.
Question 71
Question
Assume int[ ] t = {1, 2, 3, 4}. What is t.length?
Question 72
Question
Analyze the following code:
public class Test {
public static void main(String[ ] args) {
int[ ] x = {1, 2, 3, 4};
int[ ] y = x;
x = new int[2];
for (int i = 0; i < x.length; i++)
System.out.print(x[i] + " ");
}
}
Answer
-
The program displays 0 0 3 4
-
The program displays 0 0
-
The program displays 0 0 0 0
-
The program displays 1 2 3 4
Question 73
Question
Analyze the following code.
int[ ] list = new int[5];
list = new int[6];
Answer
-
The code has runtime errors because the variable list cannot be changed once it is assigned.
-
The code has compile errors because you cannot assign a different size array to list.
-
The code has compile errors because the variable list cannot be changed once it is assigned.
-
The code can compile and run fine. The second line assigns a new array to list.
Question 74
Question
In the following code, what is the printout for list1?
class Test {
public static void main(String[ ] args) {
int[ ] list1 = {1, 2, 3};
int[ ] list2 = {1, 2, 3};
list2 = list1;
list1[0] = 0; list1[1] = 1; list2[2] = 2;
for (int i = 0; i < list1.length; i++)
System.out.print(list1[i] + " ");
}
}
Question 75
Question
How many elements are in array double[ ] list = new double[5]?
Question 76
Question
The selectionSort method is defined in this section. Assume list is {3.1, 3.1, 2.5, 6.4, 2.1}, what is the content of list after the first iteration of the outer loop in the method?
Answer
-
2.1, 2.5, 3.1, 3.1, 6.4
-
2.5, 3.1, 3.1, 6.4, 2.1
-
3.1, 3.1, 2.5, 2.1, 6.4
-
3.1, 3.1, 2.5, 6.4, 2.1
Question 77
Question
Analyze the following code:
class Test {
public static void main(String[ ] args) {
System.out.println(xmethod(5));
}
public static int xmethod(int n, long t) {
System.out.println("int");
return n;
}
public static long xmethod(long n) {
System.out.println("long");
return n;
}
}
Answer
-
The program displays long followed by 5.
-
The program displays int followed by 5.
-
The program runs fine but displays things other than 5.
-
The program does not compile because the compiler cannot distinguish which xmethod to invoke.
Question 78
Question
Which statement is false?
Answer
-
Redeclaring a method parameter as a local variable in the method's body is a compilation error.
-
Placing a semicolon after the right parenthesis enclosing the parameter list of a method declaration is a syntax error.
-
Forgetting to return a value from a method that should return a value is a compilation error.
-
If a method does not return a value, the return-value-type in the method declaration can be omitted.
Question 79
Question
What is Math.ceil(3.6)?
Question 80
Question
Programs designed for maintainability are constructed from small simple pieces or modules. Modules in Java are called:
Question 81
Question
Which of the following promotions of primitive types is not allowed to occur?
Answer
-
char to int.
-
int to double.
-
short to long.
-
double to float.
Question 82
Question
What is Math.rint(3.6)?
Question 83
Question
Method log takes the logarithm of its argument with respect to what base?
Question 84
Question
Does the return statement in the following method cause compile errors?
public static void main(String[ ] args) {
int max = 0;
if (max != 0)
System.out.println(max);
else
return;
}
Question 85
Question
Analyze the following code.
public class Test {
public static void main(String[ ] args) {
System.out.println(m(2));
}
public static int m(int num) {
return num;
}
public static void m(int num) {
System.out.println(num);
}
}
Answer
-
The program runs and prints 2 once.
-
The program has a compile error because the second m method is defined, but not invoked in the main method.
-
The program has a compile error because the two methods m have the same signature.
-
The program runs and prints 2 twice.
Question 86
Question
Arguments to methods always appear within ________.
Answer
-
brackets
-
quotation marks
-
curly braces
-
parentheses
Question 87
Question
Math static method random generates a random double value in the range from 0.0
Answer
-
up to and including 1.0
-
up to but not including 1.0
-
up to and including 100.0
-
up to but not including 100.0
Question 88
Question
Which of the following primitive types is never promoted to another type?
Answer
-
double.
-
byte.
-
boolean.
-
both double and boolean
Question 89
Question
Suppose your method does not return any value, which of the following keywords can be used as a return type?
Answer
-
void
-
public
-
double
-
int
-
none of the above
Question 90
Question
A variable defined inside a method is referred to as ________.
Answer
-
a block variable
-
a global variable
-
a local variable
-
a method variable
Question 91
Question
The client can use a method without knowing how it is implemented. The details of the implementation are encapsulated in the method and hidden from the client who invokes the method. This is known as ________. (Choose all that apply.)
Answer
-
method hiding
-
information hiding
-
simplifying method
-
encapsulation
Question 92
Question
Which of the following statements about the break statement is false?
Answer
-
Common uses of the break statement are to escape early from a loop or to skip the remainder of a switch.
-
A break statement can only break out of an immediately enclosing while, for, do…while or switch statement.
-
The break statement is used to exit a repetition structure early and continue execution after the loop.
-
The break statement, when executed in a while, for or do…while, skips the remaining statements in the loop body and proceeds with the next iteration of the loop.
Question 93
Question
Consider the classes below:
public class TestA
{
public static void main( String args[] )
{
int x = 2, y = 20, counter = 0;
for ( int j = y % x; j < 100; j += ( y / x ) )
counter++;
} // end main
} // end class TestA
public class TestB
{
public static void main(String args[])
{
int counter = 0;
for ( int j = 10; j > 0; --j )
++counter;
} // end main
} // end class TestB
Which of the following statements is true?
Answer
-
The value of counter will be different at the end of each for loop for each class.
-
The value of j will be the same for each loop for all iterations
-
Both (a) and (b) are true.
-
Neither (a) nor (b) is true.
Question 94
Question
For the two code segments below:
Segment A
int q = 5;
switch( q )
{
case 1:
System.out.println( 1 );
case 2:
System.out.println( 2 );
case 3:
System.out.println( 3 );
case 4:
System.out.println( 4 );
case 5:
System.out.println( 5 );
default:
System.out.println( "default" );
} // end switch
Segment B
q = 4;
switch( q )
{
case 1:
System.out.println( 1 );
case 2:
System.out.println( 2 );
case 3:
System.out.println( 3 );
case 4:
System.out.println( 4 );
case 5:
System.out.println( 5 );
default:
System.out.println( "default" );
} // end switch
Which of the following statements is true?
Answer
-
The output for Segment B is: ?45default
-
The output for Segment B is: ?4
-
The output for Segment A is: ?default
-
The output for Segment A is: ?5?default
Question 95
Question
What is sum after the following loop terminates?
int sum = 0;
int item = 0;
do {
item++;
sum += item;
if (sum > 4) break;
}
while (item < 5);
Question 96
Question
The control variable of a counter-controlled loop should be declared as ________to prevent errors.
Answer
-
double.
-
Any of the above.
-
int.
-
float.
Question 97
Question
Which of the following statements about a do..while repetition statement is true?
Answer
-
The body of a do..while loop is executed only if the terminating condition is true.
-
The body of a do..while loop is executed only once.
-
The body of a do..while loop is always executed at least once.
-
None of the above
Question 98
Question
Which expression is equivalent to if ( ! ( grade == sentinelValue ) )?
Answer
-
! if ( grade == sentinelValue ).
-
! if ( grade !== sentinelValue ).
-
if ( grade !== sentinelValue ).
-
if ( grade != sentinelValue ).
Question 99
Question
Which of the following assignment statements is correct to assign character 5 to c?
Answer
-
char c = '5';
-
char c = 5;
-
char c = "5";
-
char c = "344";
Question 100
Question
Analyze the following code:
int i = 3434; double d = 3434;
System.out.printf("%5.1f %5.1f", i, d);
Answer
-
The code compiles and runs fine to display 3434.0 3434.0.
-
The code compiles and runs fine to display 3434 3434.0.
-
i is an integer, but the format specifier %5.1f specifies a format for double value. The code has an error.
Question 101
Question
What is "Welcome" + 1 + 1 * 2?
Answer
-
Welcome11*2
-
Welcome4
-
Welcome12
-
Welcome3
Question 102
Question
Note that the Unicode for character A is 65. The expression 'A' + 1 evaluates to ________.
Answer
-
66
-
B
-
A1
-
Illegal expression
Question 103
Question
________ returns true.
Answer
-
"peter".compareToIgnoreCase("Peter")
-
"peter".compareToIgnoreCase("peter")
-
"peter".equalsIgnoreCase("Peter")
-
"peter".equalsIgnoreCase("peter")
-
"peter".equals("peter")
Question 104
Question
To concatenate s1, s2, s3, and s4, you write ________.
Answer
-
s1.concate(s2).concate(s3).concate(s4);
-
s1.concate(s2) + s3.concate(s4);
-
((s1.concate(s2)).concate(s3)).concate(s4);
-
s1.concate(s2).(concate(s3).concate(s4));
Question 105
Question
Assume that the ASCII code for character c is 99. What is the printout of the following code?
System.out.println("a" + 'c');
Question 106
Question
Math.sin(Math.PI) returns ________.
Question 107
Question
parseDouble is a method in the ________ class.
Answer
-
Integer
-
Double
-
Math
-
System
Question 108
Question
Is 'a' larger than 'A'?
Question 109
Question
The order of the precedence (from high to low) of the operators +, *, &&, ||, & is:
Answer
-
*, +, &, &&, ||
-
*, +, &, ||, &&
-
*, +, &&, ||, &
-
&, ||, &&, *, +
-
&&, ||, &, *, +
Question 110
Question
Analyze the following code:
if (x < 100) && (x > 10)
System.out.println("x is between 10 and 100");
Answer
-
The statement has compile errors because (x<100) & (x > 10) must be enclosed inside parentheses.
-
The statement has compile errors because (x<100) & (x > 10) must be enclosed inside parentheses and the println(…) statement must be put inside a block.
-
The statement compiles fine.
-
The statement compiles fine, but has a runtime error.
Question 111
Question
The following code displays ________.
double temperature = 50;
if (temperature >= 100)
System.out.println("too hot");
else if (temperature <= 40)
System.out.println("too cold");
else
System.out.println("just right");
Question 112
Question
To check whether a char variable ch is an uppercase letter, you write ________.
Answer
-
('A' <= ch <= 'Z')
-
(ch >= 'A' && ch <= 'Z')
-
(ch >= 'A' || ch <= 'Z')
-
(ch >= 'A' && ch >= 'Z')
Question 113
Question
The statement System.out.printf("%10s", 123456) outputs ________. (Note: * represents a space)
Answer
-
****123456
-
23456*****
-
12345*****
-
123456****
Question 114
Question
The equal comparison operator in Java is ________.
Question 115
Question
To improve readability and maintainability, you should declare ________ instead of using literal values such as 3.14159.
Answer
-
classes
-
variables
-
methods
-
constants
Question 116
Question
To assign a value 1 to variable x, you write
Answer
-
1 = x;
-
x = 1;
-
x := 1;
-
x == 1;
-
1 := x;
Question 117
Question
The ________ method parses a string s to an int value.
Answer
-
integer.parseInteger(s);
-
Integer.parseInt(s);
-
integer.parseInt(s);
-
Integer.parseInteger(s);
Question 118
Question
Will System.out.println((char)4) display 4?
Question 119
Question
What is the printout of the following code:
double x = 5.5;
int y = (int)x;
System.out.println("x is " + x + " and y is " + y);
Answer
-
x is 5 and y is 6
-
x is 5.5 and y is 5
-
x is 6 and y is 6
-
x is 5.5 and y is 5.0
-
x is 6.0 and y is 6.0
Question 120
Question
What is y displayed in the following code?
public class Test1 {
public static void main(String[ ] args) {
int x = 1;
int y = x = x + 1;
System.out.println("y is " + y);
}
}
Answer
-
y is 0.
-
The program has a compile error since x is redeclared in the statement int y = x = x + 1.
-
y is 2 because x + 1 is assigned to x and then x is assigned to y.
-
y is 1 because x is assigned to y first.
Question 121
Question
24 % 5 is ________.
Question 122
Question
Which of the following statements is correct to display Welcome to Java on the console? (Choose all that apply.)
Answer
-
System.out.println("Welcome to Java");
-
System.println('Welcome to Java');
-
System.out.print('Welcome to Java');
-
System.out.println('Welcome to Java');
-
System.out.print("Welcome to Java");
Question 123
Question
Why do computers use zeros and ones?
Answer
-
because combinations of zeros and ones can represent any numbers and characters.
-
because binary numbers are the bases upon which all other number systems are built.
-
because binary numbers are simplest.
-
because digital devices have two stable states and it is natural to use one state for 0 and the other for 1.
Question 124
Question
Every statement in Java ends with ________.
Answer
-
a semicolon (;)
-
a period (.)
-
an asterisk (*)
-
a comma (,)
Question 125
Question
________ are instructions to the computer. (Choose all that apply.)
Answer
-
Programs
-
Software
-
Keyboards
-
Hardware
Question 126
Question
________ is the physical aspect of the computer that can be seen.
Answer
-
Software
-
Application program
-
Operating system
-
Hardware
Question 127
Question
The extension name of a Java source code file is
Question 128
Question
________ is a program that runs on a computer to manage and control a computer's activities.
Answer
-
Modem
-
Java
-
Operating system
-
Compiler
-
Interpreter
Question 129
Question
________ translates high-level language program into machine language program.
Answer
-
A compiler
-
The operating system
-
CPU
-
An assembler
Question 130
Question
Which of the following are storage devices? (Choose all that apply.)
Answer
-
hard disk
-
floppy disk
-
CD-ROM
-
flash stick
Question 131
Question
The ________ method displays a message dialog box. (Choose all that apply.)
Answer
-
JOptionPane.showMessage(null, "Welcome to Java!", "Example 1.2 Output", JOptionPane.INFORMATION_MESSAGE);
-
JOptionPane.displayMessageDialog(null, "Welcome to Java!", "Example 1.2 Output", JOptionPane.INFORMATION_MESSAGE);
-
JOptionPane.showMessageDialog(null, "Welcome to Java!", "Example 1.2 Output", JOptionPane.INFORMATION_MESSAGE);
-
JOptionPane.showMessageDialog(null, "Welcome to Java!");
-
JOptionPane.displayMessage(null, "Welcome to Java!", "Example 1.2 Output", JOptionPane.INFORMATION_MESSAGE);
Question 132
Question
What is y displayed in the following code?
public class Test {
public static void main(String[ ] args) {
int x = 1;
int y = x++ + x;
System.out.println("y is " + y);
}
}
Answer
-
y is 4.
-
y is 1.
-
y is 3.
-
y is 2.
Question 133
Question
Which of the following is a constant, according to Java naming conventions? (Choose all that apply.)
Answer
-
ReadInt
-
Test
-
MAX_VALUE
-
read
-
COUNT
Question 134
Question
Suppose a Scanner object is created as follows:
Scanner input = new Scanner(System.in);
What method do you use to read an int value?
Answer
-
input.nextInt();
-
input.int();
-
input.nextInteger();
-
input.integer();
Question 135
Question
The System.currentTimeMillis() returns ________.
Answer
-
the current time
-
the current time in milliseconds since midnight, January 1, 1970
-
the current time in milliseconds since midnight, January 1, 1970 GMT (the Unix time)
-
the current time in milliseconds
-
the current time in milliseconds since midnight
Question 136
Question
The Unicode of 'a' is 97. What is the Unicode for 'c'?
Question 137
Question
________ is the Java assignment operator.
Question 138
Question
The statement System.out.printf("%5d", 123456) outputs ________.
Answer
-
12345.6
-
23456
-
123456
-
12345
Question 139
Question
Which of the Boolean expressions below is incorrect? (Choose all that apply.)
Answer
-
(-10 < x < 0)
-
(true) && (3 => 4)
-
(x != 0) || (x = 0)
-
(x > 0) || (x < 0)
-
!(x > 0) && (x > 0)
Question 140
Question
"ab".compareTo("aB") is ________.
Answer
-
greater than 0
-
less than 0
-
equal to 0
-
less than or equal to 0
Question 141
Question
"smiles".substring(1, 5) returns "mile".
Question 142
Question
Which of the following is a possible output for (int)(51 * Math.random())?
Question 143
Question
Which of the following statement prints smith\exam1\test.txt?
Answer
-
System.out.println("smith\exam1\test.txt");
-
System.out.println("smith\\exam1\\test.txt");
-
System.out.println("smith\"exam1\"test.txt");
-
System.out.println("smith"\exam1"\test.txt");
Question 144
Question
Math.sqrt(4) returns ________.
Question 145
Question
'3' - '2' + 'm' / 'n' is ________.
Question 146
Question
An int variable can hold ________.
Question 147
Question
Analyze the following fragment:
double sum = 0;
double d = 0;
while (d != 10.0) {
d += 0.1;
sum += sum + d;
}
Answer
-
After the loop, sum is 0 + 0.1 + 0.2 + 0.3 + ... + 1.9
-
The program does not compile because sum and d are declared double, but assigned with integer value 0.
-
The program may not stop because of the phenomenon referred to as numerical inaccuracy for operating with floating-point numbers.
-
The program never stops because d is always 0.1 inside the loop.
Question 148
Question
After the continue outer statement is executed in the following loop, which statement is executed?
outer:
for (int i = 1; i < 10; i++) {
inner:
for (int j = 1; j < 10; j++) {
if (i * j > 50)
continue outer;
System.out.println(i * j);
}
}
next:
Answer
-
The control is in the outer loop, and the next iteration of the outer loop is executed.
-
The program terminates.
-
The statement labeled next.
-
The control is in the inner loop, and the next iteration of the inner loop is executed.
Question 149
Question
Consider the following two Java code segments:
Segment 1
int i = 0;
for ( int i = 0; i <= 20; i++ ) {
System.out.println( i );
}
Segment 2
while ( i < 20 )
{
System.out.println( i );
i++;
}
Which of the following statements are true?
Question 150
Question
Which statement prints the floating-point value 123.456 right justified with a field width of 10?
Answer
-
System.out.printf( “%10.3f”, 123.456 );
-
System.out.printf( “%f10.3”, 123.456 );
-
System.out.printf( “%d10.3”, 123.456 );
-
System.out.printf( “%10.3d”, 123.456 );
Question 151
Question
Which statement below is not true?
Answer
-
Structured programming produces programs that are easier to modify
-
Structured programming produces programs that are easier to test.
-
Structured programming promotes simplicity.
-
Structured programming requires four forms of control.
Question 152
Question
An enumeration is a special class that is introduced by the keyword ________ and a type name.
Answer
-
class.
-
classEnum.
-
enumeration.
-
enum.
Question 153
Question
When an object is concatenated with a String:
Answer
-
a compilation error occurs.
-
the object's class name is used.
-
the object's toString method is implicitly called to obtain the String representation of the object.
-
a runtime error occurs.
Question 154
Question
Suppose method1 is declared as
void method1 ( int a, float b )
Which of the following methods correctly overloads method1?
Answer
-
void method2 ( int a, float b ).
-
void method2 ( float a, int b ).
-
void method1 ( float a, int b ).
-
void method1 ( int b, float a ).
Question 155
Question
Which operator can be used in string concatenation?
Question 156
Question
(char)('a' + Math.random() * ('z' - 'a' + 1)) returns a random character ________.
Answer
-
between 'a' and 'z'
-
between 'b' and 'z'
-
between 'a' and 'y'
-
between 'b' and 'y'
Question 157
Question
Which of the following is the best for generating random integer 0 or 1?
Answer
-
(int)(Math.random() + 0.2)
-
(int)Math.random()
-
(int)Math.random() + 1
-
(int)(Math.random() + 0.8)
-
(int)(Math.random() + 0.5)
Question 158
Question
Information is passed to a method in:
Question 159
Question
The signature of a method consists of ________.
Answer
-
method name
-
method name and parameter list
-
return type, method name, and parameter list
-
parameter list
Question 160
Question
Analyze the following code:
public class Test {
public static void main(String[ ] args) {
int[ ] a = new int[4];
a[1] = 1;
a = new int[2];
System.out.println("a[1] is " + a[1]);
}
}
Answer
-
The program displays a[1] is 1.
-
The program has a runtime error because a[1] is not initialized.
-
The program displays a[1] is 0.
-
The program has a compile error because new int[2] is assigned to a.
Question 161
Question
Which of the following declarations are correct? (Choose all that apply.)
Answer
-
public static void print(double... numbers)
-
public static double... print(double d1, double d2)
-
public static void print(double... numbers, String name)
-
public static void print(String... strings, double... numbers)
-
public static void print(int n, double... numbers)
Question 162
Question
The reverse method is defined in this section. What is list1 after executing the following statements?
int[ ] list1 = {1, 2, 3, 4, 5, 6};
int[ ] list2 = reverse(list1);
Answer
-
list1 is 6 6 6 6 6 6
-
list1 is 0 0 0 0 0 0
-
list1 is 1 2 3 4 5 6
-
list1 is 6 5 4 3 2 1
Question 163
Question
Analyze the following code:
public class Test {
public static void main(String[ ] args) {
int[ ] x = {1, 2, 3, 4};
int[ ] y = x;
x = new int[2];
for (int i = 0; i < y.length; i++)
System.out.print(y[i] + " ");
}
}
Answer
-
The program displays 1 2 3 4
-
The program displays 0 0 0 0
-
The program displays 0 0
-
The program displays 0 0 3 4
Question 164
Question
Suppose int i = 5, which of the following can be used as an index for array double[ ] t = new double[100]? (Choose all that apply.)
Question 165
Question
If you declare an array double[ ] list = {3.4, 2.0, 3.5, 5.5}, the highest index in array list is ________.
Question 166
Question
Suppose a method p has the following heading:
public static int[ ] p()
What return statement may be used in p()?
Question 167
Question
Analyze the following code:
public class Test {
public static void main(String[ ] args) {
int[ ] oldList = {1, 2, 3, 4, 5};
reverse(oldList);
for (int i = 0; i < oldList.length; i++)
System.out.print(oldList[i] + " ");
}
public static void reverse(int[ ] list) {
int[ ] newList = new int[list.length];
for (int i = 0; i < list.length; i++)
newList[i] = list[list.length - 1 - i];
list = newList;
}
}
Answer
-
The program displays 1 2 3 4 5.
-
The program displays 1 2 3 4 5 and then raises an ArrayIndexOutOfBoundsException.
-
The program displays 5 4 3 2 1.
-
The program displays 5 4 3 2 1 and then raises an ArrayIndexOutOfBoundsException.
Question 168
Question
Analyze the following code: (Choose all that apply.)
public class Test {
public static void main(String[ ] args) {
A a = new A();
a.print();
}
}
class A {
String s;
A(String s) {
this.s = s;
}
void print() {
System.out.println(s);
}
}
Answer
-
The program has a compilation error because class A does not have a default constructor.
-
The program would compile and run if you change A a = new A() to A a = new A("5").
-
The program compiles and runs fine and prints nothing.
-
The program has a compilation error because class A is not a public class.
Question 169
Question
Which of the following statements are true? (Choose all that apply.)
Answer
-
Data fields have default values.
-
You may assign an int value to a reference variable.
-
Local variables do not have default values.
-
A variable of a reference type holds a reference to where an object is stored in the memory.
-
A variable of a primitive type holds a value of the primitive type.
Question 170
Question
Given the declaration Circle x = new Circle(), which of the following statement is most accurate?
Answer
-
You can assign an int value to x.
-
x contains a reference to a Circle object.
-
x contains an int value.
-
x contains an object of the Circle type.
Question 171
Question
The keyword ________ is required to declare a class.
Answer
-
private
-
class
-
All of the above.
-
public
Question 172
Question
In this question, assume a class, Book, has been defined. Which set of statements creates an array of Book objects?
Answer
-
Book[] books;
books = new Book()[ numberElements ];
-
Book[] books;
books = new Book[ numberElements ];
-
All of the above.
-
new Book() books[];
books = new Book[ numberElements ];
Question 173
Question
What is wrong in the following code?
class TempClass {
int i;
public void TempClass(int j) {
int i = j;
}
}
public class C {
public static void main(String[ ] args) {
TempClass temp = new TempClass(2);
}
}
Answer
-
The program has a compilation error because TempClass does not have a default constructor.
-
The program has a compilation error because TempClass does not have a constructor with an int argument.
-
The program compiles fine, but it does not run because class C is not public.
-
The program compiles and runs fine.
Question 174
Question
What is the default initial value of a String instance variable?
Answer
-
"default"
-
""
-
null
-
default
Question 175
Question
You should add the static keyword in the place of ? in line ________ in the following code:
1 public class Test {
2 private int age;
3
4 public ? int square(int n) {
5 return n * n;
6 }
7
8 public ? int getAge() {
9 }
10}
Question 176
Question
The boolean values can be displayed with the ________ format specifier.
Question 177
Question
What is the number of iterations in the following loop:
for (int i = 1; i <= n; i++) {
// iteration
}
Question 178
Question
What modifier should you use on a class so that a class in the same package can access it but a class in a different package cannot access it?
Question 179
Question
Which of the following is true?
Answer
-
Pseudocode is used to describe an algorithm.
-
Pseudocode is translatable by the programmer into a programming language (like Java).
-
Pseudocode is used to describe executable statements that will eventually be translated by the programmer into a program.
-
All of the above.
Question 180
Question
Which of the following is a double-selection control statement?
Answer
-
do..while.
-
for.
-
if...else.
-
if.
Question 181
Question
Suppose s1 and s2 are two strings. What is the result of the following code?
s1.equals(s2) == s2.equals(s1)
Question 182
Question
A class within a package must be declared public if
Answer
-
It will be used only by other classes in the same package.
-
It will be used by classes that are not in the same package.
-
It is in the same directory as the other classes in the package.
-
It has a unique name.
Question 183
Question
A String constructor cannot be passed variables of type:
Answer
-
char arrays.
-
int arrays.
-
byte arrays.
-
Strings.
Question 184
Question
A programmer-defined constructor that has no arguments is called a ________.
Question 185
Question
Is the following loop correct?
for (; ; );
Question 186
Question
You can create an ArrayList using ________.
Answer
-
ArrayList()
-
new ArrayList()
-
new ArrayList[100]
-
new ArrayList[ ]
Question 187
Question
List the following operators in the order that they will be evaluated: -, *, /, +, %. Assume that if two operations have the same precedence, the one listed first will be evaluated first.
Answer
-
+, -, /, *, %.
-
-, +, %, *, /.
-
-, *, %, +, /.
-
*, /, %, -, +.
Question 188
Question
Which of the following is not a Java primitive type?
Question 189
Question
Which of the following statements are correct? (Choose all that apply.)
Answer
-
The nextInt() method in the Random class returns the next random int value.
-
The nextDouble() method in the Random class returns the next random double value.
-
When creating a Random object, you have to specify the seed or use the default seed.
-
If two Random objects have the same seed, the sequence of the random numbers obtained from these two objects are identical.
Question 190
Question
What exception type does the following program throw?
public class Test {
public static void main(String[ ] args) {
Object o = new Object();
String d = (String)o;
}
}
Question 191
Question
Which of the following is not a benefit of goto-less programming?
Question 192
Question
Consider integer array values, which contains 5 elements. Which statements successfully swap the contents of the array at index 3 and index 4?
Answer
-
values[ 3 ] = values[ 4 ];
values[ 4 ] = values[ 3 ];
-
values[ 4 ] = values[ 3 ];
values[ 3 ] = values[ 4 ];
-
int temp = values[ 3 ];
values[ 3 ] = values[ 4 ];
values[ 4 ] = temp;
-
int temp = values[ 3 ];
values[ 3 ] = values[ 4 ];
values[ 4 ] = values[ 3 ];
Question 193
Question
To prevent a class from being instantiated, ________
Answer
-
use the static modifier on the constructor.
-
use the public modifier on the constructor.
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don't use any modifiers on the constructor.
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use the private modifier on the constructor.
Question 194
Question
When compiling a class in a package, the javac command-line option ________ causes the javac compiler to create appropriate directories based on the class's package declaration.
Question 195
Question
An advantage of inheritance is that:
Answer
-
All methods can be inherited.
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All instance variables can be uniformly accessed by subclasses and superclasses.
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Objects of a subclass can be treated like objects of their superclass.
-
None of the above.
Question 196
Question
An instance of ________ are unchecked exceptions. (Choose all that apply.)
Answer
-
Throwable
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NumberFormatException
-
Error
-
Exception
-
RuntimeException
Question 197
Question
Assume StringBuilder strBuf is "ABCCEFC", after invoking ________, strBuf contains "ABTTEFT".
Answer
-
strBuf.replace(2, 7, "TTEFT")
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strBuf.replace("CC", "TT")
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strBuf.replace("C", "T")
-
strBuf.replace('C', "TT")
-
strBuf.replace('C', 'T')
Question 198
Question
Using public set methods provides data integrity if:
Answer
-
The instance variables are public.
-
The instance variables are private.
-
The methods perform validity checking.
-
Both b and c.
Question 199
Question
Which of the following is the correct header of the main method? (Choose all that apply.)
Answer
-
public static void main(String[ ] x)
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public static void main(String args[ ])
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static void main(String[ ] args)
-
public static void main(String x[ ])
-
public static void main(String[ ] args)
Question 200
Question
What is x after the following statements?
int x = 1;
int y = 2;
x *= y + 1;
Answer
-
x is 2.
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x is 3.
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x is 1.
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x is 4.