4158070
Pregunta 1
Pregunta
To add a value 1 to variable x, you write (Choose all that apply.)
Respuesta
-
x += 1;
-
x = 1 + x;
-
x := 1;
-
x = x + 1;
-
1 + x = x;
Pregunta 2
Pregunta
An overloaded method is one that
Respuesta
-
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.
Pregunta 3
Pregunta
In Java, the word true is ________.
Respuesta
-
same as value 0
-
same as value 1
-
a Boolean literal
-
a Java keyword
Pregunta 4
Pregunta
The ________ method parses a string s to a double value.
Respuesta
-
double.parseDouble(s);
-
double.parse(s);
-
Double.parsedouble(s);
-
Double.parseDouble(s);
Pregunta 5
Pregunta
Suppose variable gender is MALE and age equals 60, how is the expression
( gender == FEMALE ) && ( age >= 65 )
evaluated?
Respuesta
-
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.
Pregunta 6
Pregunta
Will the following program terminate?
int balance = 10;
while (true) {
if (balance < 9) continue;
balance = balance - 9;
}
Respuesta
-
Yes
-
No
Pregunta 7
Pregunta
What is the output of the following code?
boolean even = false;
System.out.println((even ? "true" : "false"));
Respuesta
-
true
-
true false
-
false
-
nothing
Pregunta 8
Pregunta
Which command compiles the Java source code file Welcome.java?
Respuesta
-
cd Welcome.java
-
javac Welcome.java
-
java Welcome.java
-
compile Welcome.java
Pregunta 9
Pregunta
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?
Respuesta
-
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.
Pregunta 10
Pregunta
Suppose s1 and s2 are two strings. Which of the following statements or expressions is incorrect? (Choose all that apply.)
Respuesta
-
boolean b = s1.compareTo(s2);
-
char c = s1[0];
-
char c = s1.charAt(s1.length());
-
String s3 = s1 - s2;
Pregunta 11
Pregunta
Which statement is true?
Respuesta
-
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.
Pregunta 12
Pregunta
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!" );
Respuesta
-
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.
Pregunta 13
Pregunta
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);
Respuesta
-
'a'
-
'v'
-
Nothing will be assigned to x, because the execution causes the runtime error StringIndexOutofBoundsException.
Pregunta 14
Pregunta
Which of these statements best defines scope?
Respuesta
-
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.
Pregunta 15
Pregunta
What is the value of (double)5/2?
Respuesta
-
2.5
-
2
-
3
-
2.0
-
3.0
Pregunta 16
Pregunta
What does the expression x %= 10 do?
Respuesta
-
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.
Pregunta 17
Pregunta
Which of the following is not a package in the Java API?
Respuesta
-
java.characters.
-
java.awt.
-
javax.swing.event.
-
java.lang.
Pregunta 18
Pregunta
Suppose x=10 and y=10 what is x after evaluating the expression (y >= 10) || (x-- > 10)?
Respuesta
-
11
-
9
-
10
Pregunta 19
Pregunta
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.
Respuesta
-
a stack
-
an array
-
a heap
-
storage area
Pregunta 20
Pregunta
Counter-controlled repetition requires
Respuesta
-
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.
Pregunta 21
Pregunta
Which of the following assignment statements is correct? (Choose all that apply.)
Respuesta
-
char c = 'd';
-
char c = "100";
-
char c = "d";
-
char c = 100;
Pregunta 22
Pregunta
To add 0.01 + 0.02 + ... + 1.00, what order should you use to add the numbers to get better accuracy?
Respuesta
-
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.
Pregunta 23
Pregunta
(int)(Math.random() * (65535 + 1)) returns a random number ________.
Respuesta
-
between 1 and 65535
-
between 0 and 65536
-
between 0 and 65535
-
between 1 and 65536
Pregunta 24
Pregunta
What is the return value of "SELECT".substring(4, 4)?
Respuesta
-
T
-
C
-
an empty string
-
E
Pregunta 25
Pregunta
What is the value of (double)(5/2)?
Respuesta
-
2
-
2.0
-
3
-
2.5
-
3.0
Pregunta 26
Pregunta
Which of the following statements will print a single line containing "hello there"?
Respuesta
-
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" );
Pregunta 27
Pregunta
Which of the following operators are right-associative?
Respuesta
-
*
-
%
-
&&
-
+
-
=
Pregunta 28
Pregunta
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");
}
}
}
Respuesta
-
The finally clause is executed
-
Welcome to Java followed by The finally clause is executed in the next line
-
None of the above
-
Welcome to Java
Pregunta 29
Pregunta
Which of the following exceptions is a checked exception?
Respuesta
-
ArithmeticException.
-
IOException.
-
InputMismatchException.
-
RuntimeException.
Pregunta 30
Pregunta
What exception type does the following program throw?
public class Test {
public static void main(String[ ] args) {
System.out.println(1 / 0);
}
}
Respuesta
-
ClassCastException
-
No exception
-
ArithmeticException
-
StringIndexOutOfBoundsException
-
ArrayIndexOutOfBoundsException
Pregunta 31
Pregunta
What is wrong in the following program?
class Test {
public static void main (String[ ] args) {
try {
System.out.println("Welcome to Java");
}
}
}
Respuesta
-
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.
Pregunta 32
Pregunta
Which of the following statements is true?
Respuesta
-
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.
Pregunta 33
Pregunta
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");
}
}
}
Respuesta
-
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.
Pregunta 34
Pregunta
What is the difference between a try block and a try statement?
Respuesta
-
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.
Pregunta 35
Pregunta
If the catch-or-declare requirement for a checked exception is not satisfied:
Respuesta
-
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.
Pregunta 36
Pregunta
When an exception occurs it is said to have been:
Respuesta
-
handled.
-
thrown.
-
caught.
-
declared.
Pregunta 37
Pregunta
Exceptions can be thrown by:
Respuesta
-
All of the above.
-
code in a try block.
-
the Java Virtual Machine.
-
calls from a try block to other methods.
Pregunta 38
Pregunta
Analyze the following code:
class Test {
public static void main(String[ ] args)
throws MyException {
System.out.println("Welcome to Java");
}
}
class MyException extends Error {
}
Respuesta
-
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.
Pregunta 39
Pregunta
The following code causes Java to throw ________.
int number = Integer.MAX_VALUE + 1;
Respuesta
-
Error
-
RuntimeException
-
no exceptions
-
Exception
-
Throwable
Pregunta 40
Pregunta
A Java exception is an instance of ________.
Respuesta
-
RuntimeException
-
Error
-
NumberFormatException
-
Exception
-
Throwable
Pregunta 41
Pregunta
Which of the following statements is true?
Respuesta
-
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.
Pregunta 42
Pregunta
Suppose ArrayList x contains two strings [Beijing, Singapore]. Which of the following method will cause runtime errors? (Choose all that apply.)
Respuesta
-
x.get(1)
-
x.size()
-
x.remove(2)
-
x.get(2)
-
x.set(2, "New York");
Pregunta 43
Pregunta
Which keyword is used to specify that a class will define the methods of an interface?
Respuesta
-
implements.
-
extends.
-
defines.
-
uses.
Pregunta 44
Pregunta
A(n) ____________________ class cannot be instantiated.
Respuesta
-
polymorphic.
-
abstract.
-
concrete.
-
final.
Pregunta 45
Pregunta
Failure to prefix the superclass method name with the keyword super and a dot (.) separator when referencing the superclass's method causes ________.
Respuesta
-
a syntax error.
-
a compile-time error.
-
a runtime error.
-
infinite recursion.
Pregunta 46
Pregunta
The equals method is defined in the Object class. Which of the following is correct to override it in the String class?
Respuesta
-
public static boolean equals(String other)
-
public boolean equals(String other)
-
public static boolean equals(Object other)
-
public boolean equals(Object other)
Pregunta 47
Pregunta
Inheritance means ________.
Respuesta
-
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
Pregunta 48
Pregunta
Analyze the following code:
Cylinder cy = new Cylinder(1, 1);
Circle c = cy;
Respuesta
-
The code has a runtime error.
-
The code has a compile error.
-
The code is fine.
Pregunta 49
Pregunta
Encapsulation means ________.
Respuesta
-
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
Pregunta 50
Pregunta
private fields of a superclass can be accessed in a subclass
Respuesta
-
by calling public or protected methods declared in the superclass.
-
All of the above.
-
directly.
-
by calling private methods declared in the superclass.
Pregunta 51
Pregunta
Suppose ArrayList x contains two strings [Beijing, Singapore]. Which of the following method will cause the list to become [Beijing]? (Choose all that apply.)
Respuesta
-
x.remove(1)
-
x.remove("Singapore")
-
x.remove(0)
-
x.remove(2)
Pregunta 52
Pregunta
You can assign ________ to a variable of Object[ ] type. (Choose all that apply.)
Respuesta
-
new java.util.Date[100]
-
new String[100]
-
new double[100]
-
new char[100]
-
new int[100]
Pregunta 53
Pregunta
Which of the following statements are true? (Choose all that apply.)
Respuesta
-
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.
Pregunta 54
Pregunta
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?
Respuesta
-
c4 instanceof C2
-
c1 instanceof C1
-
c3 instanceof C1
-
c2 instanceof C1
Pregunta 55
Pregunta
Object-oriented programming allows you to derive new classes from existing classes. This is called ________.
Respuesta
-
generalization
-
encapsulation
-
inheritance
-
abstraction
Pregunta 56
Pregunta
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);
}
}
Respuesta
-
j is 3
-
j is 1
-
j is 2
-
j is 0
Pregunta 57
Pregunta
The UML represents operations by listing the operation name, followed by a ________-separated list of parameters in parentheses, a ________ and the return type.
Respuesta
-
comma, colon.
-
colon, semicolon.
-
colon, colon.
-
comma, semicolon.
Pregunta 58
Pregunta
Analyze the following code:
class Circle {
private double radius;
public Circle(double radius) {
radius = radius;
}
}
Respuesta
-
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.
Pregunta 59
Pregunta
Which diagram models system structure?
Respuesta
-
State machine diagram.
-
Activity diagram.
-
Class diagram.
-
Sequence diagram.
Pregunta 60
Pregunta
Which of the following is the first stage of the software life cycle?
Respuesta
-
testing.
-
implementation.
-
requirements gathering.
-
design.
Pregunta 61
Pregunta
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);
}
}
Respuesta
-
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.
Pregunta 62
Pregunta
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);
}
}
Respuesta
-
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.
Pregunta 63
Pregunta
Assume java.util.Date[ ] dates = new java.util.Date[10], which of the following statements are true? (Choose all that apply.)
Respuesta
-
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.
Pregunta 64
Pregunta
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();
}
}
Respuesta
-
B
-
A
-
neither
Pregunta 65
Pregunta
________ is a construct that defines objects of the same type.
Respuesta
-
A class
-
A method
-
A data field
-
An object
Pregunta 66
Pregunta
Which two Java primitive types store floating-point numbers?
Respuesta
-
decimal and float.
-
point and double.
-
decimal and point.
-
float and double.
Pregunta 67
Pregunta
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++;
}
}
Respuesta
-
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
Pregunta 68
Pregunta
Which of the following statements are true? (Choose all that apply.)
Respuesta
-
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.
Pregunta 69
Pregunta
An object is an instance of a ________.
Respuesta
-
method
-
program
-
data
-
class
Pregunta 70
Pregunta
When you pass an array to a method, the method receives ________.
Respuesta
-
the length of the array
-
the reference of the array
-
a copy of the first element
-
a copy of the array
Pregunta 71
Pregunta
Assume int[ ] t = {1, 2, 3, 4}. What is t.length?
Respuesta
-
4
-
0
-
5
-
3
Pregunta 72
Pregunta
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] + " ");
}
}
Respuesta
-
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
Pregunta 73
Pregunta
Analyze the following code.
int[ ] list = new int[5];
list = new int[6];
Respuesta
-
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.
Pregunta 74
Pregunta
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] + " ");
}
}
Respuesta
-
0 1 2
-
1 2 3
-
1 1 1
-
0 1 3
Pregunta 75
Pregunta
How many elements are in array double[ ] list = new double[5]?
Respuesta
-
0
-
4
-
5
-
6
Pregunta 76
Pregunta
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?
Respuesta
-
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
Pregunta 77
Pregunta
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;
}
}
Respuesta
-
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.
Pregunta 78
Pregunta
Which statement is false?
Respuesta
-
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.
Pregunta 79
Pregunta
What is Math.ceil(3.6)?
Respuesta
-
5.0
-
3.0
-
4.0
-
3
Pregunta 80
Pregunta
Programs designed for maintainability are constructed from small simple pieces or modules. Modules in Java are called:
Respuesta
-
both methods and classes.
-
arguments.
-
classes.
-
methods.
Pregunta 81
Pregunta
Which of the following promotions of primitive types is not allowed to occur?
Respuesta
-
char to int.
-
int to double.
-
short to long.
-
double to float.
Pregunta 82
Pregunta
What is Math.rint(3.6)?
Respuesta
-
4.0
-
3.0
-
5.0
-
3
Pregunta 83
Pregunta
Method log takes the logarithm of its argument with respect to what base?
Respuesta
-
pi
-
2
-
e
-
10
Pregunta 84
Pregunta
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;
}
Respuesta
-
Yes
-
No
Pregunta 85
Pregunta
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);
}
}
Respuesta
-
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.
Pregunta 86
Pregunta
Arguments to methods always appear within ________.
Respuesta
-
brackets
-
quotation marks
-
curly braces
-
parentheses
Pregunta 87
Pregunta
Math static method random generates a random double value in the range from 0.0
Respuesta
-
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
Pregunta 88
Pregunta
Which of the following primitive types is never promoted to another type?
Respuesta
-
double.
-
byte.
-
boolean.
-
both double and boolean
Pregunta 89
Pregunta
Suppose your method does not return any value, which of the following keywords can be used as a return type?
Respuesta
-
void
-
public
-
double
-
int
-
none of the above
Pregunta 90
Pregunta
A variable defined inside a method is referred to as ________.
Respuesta
-
a block variable
-
a global variable
-
a local variable
-
a method variable
Pregunta 91
Pregunta
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.)
Respuesta
-
method hiding
-
information hiding
-
simplifying method
-
encapsulation
Pregunta 92
Pregunta
Which of the following statements about the break statement is false?
Respuesta
-
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.
Pregunta 93
Pregunta
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?
Respuesta
-
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.
Pregunta 94
Pregunta
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?
Respuesta
-
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
Pregunta 95
Pregunta
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);
Respuesta
-
7
-
8
-
5
-
6
Pregunta 96
Pregunta
The control variable of a counter-controlled loop should be declared as ________to prevent errors.
Respuesta
-
double.
-
Any of the above.
-
int.
-
float.
Pregunta 97
Pregunta
Which of the following statements about a do..while repetition statement is true?
Respuesta
-
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
Pregunta 98
Pregunta
Which expression is equivalent to if ( ! ( grade == sentinelValue ) )?
Respuesta
-
! if ( grade == sentinelValue ).
-
! if ( grade !== sentinelValue ).
-
if ( grade !== sentinelValue ).
-
if ( grade != sentinelValue ).
Pregunta 99
Pregunta
Which of the following assignment statements is correct to assign character 5 to c?
Respuesta
-
char c = '5';
-
char c = 5;
-
char c = "5";
-
char c = "344";
Pregunta 100
Pregunta
Analyze the following code:
int i = 3434; double d = 3434;
System.out.printf("%5.1f %5.1f", i, d);
Respuesta
-
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.
Pregunta 101
Pregunta
What is "Welcome" + 1 + 1 * 2?
Respuesta
-
Welcome11*2
-
Welcome4
-
Welcome12
-
Welcome3
Pregunta 102
Pregunta
Note that the Unicode for character A is 65. The expression 'A' + 1 evaluates to ________.
Respuesta
-
66
-
B
-
A1
-
Illegal expression
Pregunta 103
Pregunta
________ returns true.
Respuesta
-
"peter".compareToIgnoreCase("Peter")
-
"peter".compareToIgnoreCase("peter")
-
"peter".equalsIgnoreCase("Peter")
-
"peter".equalsIgnoreCase("peter")
-
"peter".equals("peter")
Pregunta 104
Pregunta
To concatenate s1, s2, s3, and s4, you write ________.
Respuesta
-
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));
Pregunta 105
Pregunta
Assume that the ASCII code for character c is 99. What is the printout of the following code?
System.out.println("a" + 'c');
Respuesta
-
a99
-
ac
-
9799
-
196
Pregunta 106
Pregunta
Math.sin(Math.PI) returns ________.
Respuesta
-
0.0
-
1.0
-
0.5
-
0.4
Pregunta 107
Pregunta
parseDouble is a method in the ________ class.
Respuesta
-
Integer
-
Double
-
Math
-
System
Pregunta 108
Pregunta
Is 'a' larger than 'A'?
Respuesta
-
Yes
-
No
Pregunta 109
Pregunta
The order of the precedence (from high to low) of the operators +, *, &&, ||, & is:
Respuesta
-
*, +, &, &&, ||
-
*, +, &, ||, &&
-
*, +, &&, ||, &
-
&, ||, &&, *, +
-
&&, ||, &, *, +
Pregunta 110
Pregunta
Analyze the following code:
if (x < 100) && (x > 10)
System.out.println("x is between 10 and 100");
Respuesta
-
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.
Pregunta 111
Pregunta
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");
Respuesta
-
too hot
-
too hot too cold just right
-
just right
-
too cold
Pregunta 112
Pregunta
To check whether a char variable ch is an uppercase letter, you write ________.
Respuesta
-
('A' <= ch <= 'Z')
-
(ch >= 'A' && ch <= 'Z')
-
(ch >= 'A' || ch <= 'Z')
-
(ch >= 'A' && ch >= 'Z')
Pregunta 113
Pregunta
The statement System.out.printf("%10s", 123456) outputs ________. (Note: * represents a space)
Respuesta
-
****123456
-
23456*****
-
12345*****
-
123456****
Pregunta 114
Pregunta
The equal comparison operator in Java is ________.
Respuesta
-
<>
-
==
-
!=
-
^=
Pregunta 115
Pregunta
To improve readability and maintainability, you should declare ________ instead of using literal values such as 3.14159.
Respuesta
-
classes
-
variables
-
methods
-
constants
Pregunta 116
Pregunta
To assign a value 1 to variable x, you write
Respuesta
-
1 = x;
-
x = 1;
-
x := 1;
-
x == 1;
-
1 := x;
Pregunta 117
Pregunta
The ________ method parses a string s to an int value.
Respuesta
-
integer.parseInteger(s);
-
Integer.parseInt(s);
-
integer.parseInt(s);
-
Integer.parseInteger(s);
Pregunta 118
Pregunta
Will System.out.println((char)4) display 4?
Respuesta
-
No
-
Yes
Pregunta 119
Pregunta
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);
Respuesta
-
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
Pregunta 120
Pregunta
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);
}
}
Respuesta
-
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.
Pregunta 121
Pregunta
24 % 5 is ________.
Respuesta
-
1
-
3
-
2
-
0
-
4
Pregunta 122
Pregunta
Which of the following statements is correct to display Welcome to Java on the console? (Choose all that apply.)
Respuesta
-
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");
Pregunta 123
Pregunta
Why do computers use zeros and ones?
Respuesta
-
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.
Pregunta 124
Pregunta
Every statement in Java ends with ________.
Respuesta
-
a semicolon (;)
-
a period (.)
-
an asterisk (*)
-
a comma (,)
Pregunta 125
Pregunta
________ are instructions to the computer. (Choose all that apply.)
Respuesta
-
Programs
-
Software
-
Keyboards
-
Hardware
Pregunta 126
Pregunta
________ is the physical aspect of the computer that can be seen.
Respuesta
-
Software
-
Application program
-
Operating system
-
Hardware
Pregunta 127
Pregunta
The extension name of a Java source code file is
Respuesta
-
.class
-
.obj
-
.java
-
.exe
Pregunta 128
Pregunta
________ is a program that runs on a computer to manage and control a computer's activities.
Respuesta
-
Modem
-
Java
-
Operating system
-
Compiler
-
Interpreter
Pregunta 129
Pregunta
________ translates high-level language program into machine language program.
Respuesta
-
A compiler
-
The operating system
-
CPU
-
An assembler
Pregunta 130
Pregunta
Which of the following are storage devices? (Choose all that apply.)
Respuesta
-
hard disk
-
floppy disk
-
CD-ROM
-
flash stick
Pregunta 131
Pregunta
The ________ method displays a message dialog box. (Choose all that apply.)
Respuesta
-
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);
Pregunta 132
Pregunta
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);
}
}
Respuesta
-
y is 4.
-
y is 1.
-
y is 3.
-
y is 2.
Pregunta 133
Pregunta
Which of the following is a constant, according to Java naming conventions? (Choose all that apply.)
Respuesta
-
ReadInt
-
Test
-
MAX_VALUE
-
read
-
COUNT
Pregunta 134
Pregunta
Suppose a Scanner object is created as follows:
Scanner input = new Scanner(System.in);
What method do you use to read an int value?
Respuesta
-
input.nextInt();
-
input.int();
-
input.nextInteger();
-
input.integer();
Pregunta 135
Pregunta
The System.currentTimeMillis() returns ________.
Respuesta
-
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
Pregunta 136
Pregunta
The Unicode of 'a' is 97. What is the Unicode for 'c'?
Respuesta
-
96
-
97
-
99
-
98
Pregunta 137
Pregunta
________ is the Java assignment operator.
Respuesta
-
:=
-
==
-
=:
-
=
Pregunta 138
Pregunta
The statement System.out.printf("%5d", 123456) outputs ________.
Respuesta
-
12345.6
-
23456
-
123456
-
12345
Pregunta 139
Pregunta
Which of the Boolean expressions below is incorrect? (Choose all that apply.)
Respuesta
-
(-10 < x < 0)
-
(true) && (3 => 4)
-
(x != 0) || (x = 0)
-
(x > 0) || (x < 0)
-
!(x > 0) && (x > 0)
Pregunta 140
Pregunta
"ab".compareTo("aB") is ________.
Respuesta
-
greater than 0
-
less than 0
-
equal to 0
-
less than or equal to 0
Pregunta 141
Pregunta
"smiles".substring(1, 5) returns "mile".
Respuesta
-
true
-
false
Pregunta 142
Pregunta
Which of the following is a possible output for (int)(51 * Math.random())?
Respuesta
-
0
-
50
-
100
-
500
Pregunta 143
Pregunta
Which of the following statement prints smith\exam1\test.txt?
Respuesta
-
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");
Pregunta 144
Pregunta
Math.sqrt(4) returns ________.
Respuesta
-
2
-
2.0
-
1
-
1.0
Pregunta 145
Pregunta
'3' - '2' + 'm' / 'n' is ________.
Respuesta
-
0
-
1
-
2
-
3
Pregunta 146
Pregunta
An int variable can hold ________.
Respuesta
-
'x'
-
120
-
120.0
Pregunta 147
Pregunta
Analyze the following fragment:
double sum = 0;
double d = 0;
while (d != 10.0) {
d += 0.1;
sum += sum + d;
}
Respuesta
-
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.
Pregunta 148
Pregunta
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:
Respuesta
-
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.
Pregunta 149
Pregunta
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?
Respuesta
-
The output from these segments is not the same.
-
The scope of the control variable i is different for the two segments.
-
They are both true
-
Neither are true
Pregunta 150
Pregunta
Which statement prints the floating-point value 123.456 right justified with a field width of 10?
Respuesta
-
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 );
Pregunta 151
Pregunta
Which statement below is not true?
Respuesta
-
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.
Pregunta 152
Pregunta
An enumeration is a special class that is introduced by the keyword ________ and a type name.
Respuesta
-
class.
-
classEnum.
-
enumeration.
-
enum.
Pregunta 153
Pregunta
When an object is concatenated with a String:
Respuesta
-
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.
Pregunta 154
Pregunta
Suppose method1 is declared as
void method1 ( int a, float b )
Which of the following methods correctly overloads method1?
Respuesta
-
void method2 ( int a, float b ).
-
void method2 ( float a, int b ).
-
void method1 ( float a, int b ).
-
void method1 ( int b, float a ).
Pregunta 155
Pregunta
Which operator can be used in string concatenation?
Respuesta
-
++.
-
+=.
-
=+.
-
*.
Pregunta 156
Pregunta
(char)('a' + Math.random() * ('z' - 'a' + 1)) returns a random character ________.
Respuesta
-
between 'a' and 'z'
-
between 'b' and 'z'
-
between 'a' and 'y'
-
between 'b' and 'y'
Pregunta 157
Pregunta
Which of the following is the best for generating random integer 0 or 1?
Respuesta
-
(int)(Math.random() + 0.2)
-
(int)Math.random()
-
(int)Math.random() + 1
-
(int)(Math.random() + 0.8)
-
(int)(Math.random() + 0.5)
Pregunta 158
Pregunta
Information is passed to a method in:
Respuesta
-
the method body.
-
the method name.
-
the arguments to the method.
-
that method's return.
Pregunta 159
Pregunta
The signature of a method consists of ________.
Respuesta
-
method name
-
method name and parameter list
-
return type, method name, and parameter list
-
parameter list
Pregunta 160
Pregunta
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]);
}
}
Respuesta
-
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.
Pregunta 161
Pregunta
Which of the following declarations are correct? (Choose all that apply.)
Respuesta
-
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)
Pregunta 162
Pregunta
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);
Respuesta
-
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
Pregunta 163
Pregunta
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] + " ");
}
}
Respuesta
-
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
Pregunta 164
Pregunta
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.)
Respuesta
-
(int)(Math.random() * 100))
-
Math.random() * 100
-
i
-
i + 6.5
-
i + 10
Pregunta 165
Pregunta
If you declare an array double[ ] list = {3.4, 2.0, 3.5, 5.5}, the highest index in array list is ________.
Respuesta
-
4
-
2
-
3
-
0
-
1
Pregunta 166
Pregunta
Suppose a method p has the following heading:
public static int[ ] p()
What return statement may be used in p()?
Respuesta
-
return int[ ]{1, 2, 3};
-
return {1, 2, 3};
-
return 1;
-
return new int[ ]{1, 2, 3};
Pregunta 167
Pregunta
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;
}
}
Respuesta
-
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.
Pregunta 168
Pregunta
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);
}
}
Respuesta
-
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.
Pregunta 169
Pregunta
Which of the following statements are true? (Choose all that apply.)
Respuesta
-
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.
Pregunta 170
Pregunta
Given the declaration Circle x = new Circle(), which of the following statement is most accurate?
Respuesta
-
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.
Pregunta 171
Pregunta
The keyword ________ is required to declare a class.
Respuesta
-
private
-
class
-
All of the above.
-
public
Pregunta 172
Pregunta
In this question, assume a class, Book, has been defined. Which set of statements creates an array of Book objects?
Respuesta
-
Book[] books; books = new Book()[ numberElements ];
-
Book[] books; books = new Book[ numberElements ];
-
All of the above.
-
new Book() books[]; books = new Book[ numberElements ];
Pregunta 173
Pregunta
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);
}
}
Respuesta
-
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.
Pregunta 174
Pregunta
What is the default initial value of a String instance variable?
Respuesta
-
"default"
-
""
-
null
-
default
Pregunta 175
Pregunta
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}
Respuesta
-
in both line 4 and line 8
-
in line 8
-
in line 4
-
none
Pregunta 176
Pregunta
The boolean values can be displayed with the ________ format specifier.
Respuesta
-
%a.
-
%b.
-
%c.
-
%bool.
Pregunta 177
Pregunta
What is the number of iterations in the following loop:
for (int i = 1; i <= n; i++) {
// iteration
}
Respuesta
-
n + 1
-
2*n
-
n
-
n - 1
Pregunta 178
Pregunta
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?
Respuesta
-
protected
-
private
-
public
-
Use the default modifier.
Pregunta 179
Pregunta
Which of the following is true?
Respuesta
-
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.
Pregunta 180
Pregunta
Which of the following is a double-selection control statement?
Respuesta
-
do..while.
-
for.
-
if...else.
-
if.
Pregunta 181
Pregunta
Suppose s1 and s2 are two strings. What is the result of the following code?
s1.equals(s2) == s2.equals(s1)
Respuesta
-
true
-
false
Pregunta 182
Pregunta
A class within a package must be declared public if
Respuesta
-
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.
Pregunta 183
Pregunta
A String constructor cannot be passed variables of type:
Respuesta
-
char arrays.
-
int arrays.
-
byte arrays.
-
Strings.
Pregunta 184
Pregunta
A programmer-defined constructor that has no arguments is called a ________.
Respuesta
-
zero-argument constructor.
-
no-argument constructor.
-
default constructor.
-
main constructor.
Pregunta 185
Pregunta
Is the following loop correct?
for (; ; );
Respuesta
-
Yes
-
No
Pregunta 186
Pregunta
You can create an ArrayList using ________.
Respuesta
-
ArrayList()
-
new ArrayList()
-
new ArrayList[100]
-
new ArrayList[ ]
Pregunta 187
Pregunta
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.
Respuesta
-
+, -, /, *, %.
-
-, +, %, *, /.
-
-, *, %, +, /.
-
*, /, %, -, +.
Pregunta 188
Pregunta
Which of the following is not a Java primitive type?
Respuesta
-
char
-
byte
-
real
-
double
Pregunta 189
Pregunta
Which of the following statements are correct? (Choose all that apply.)
Respuesta
-
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.
Pregunta 190
Pregunta
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;
}
}
Respuesta
-
ClassCastException
-
No exception
-
ArrayIndexOutOfBoundsException
-
ArithmeticException
-
StringIndexOutOfBoundsException
Pregunta 191
Pregunta
Which of the following is not a benefit of goto-less programming?
Respuesta
-
Easier to debug and modify
-
Shorter
-
Clearer
-
More likely to be bug free
Pregunta 192
Pregunta
Consider integer array values, which contains 5 elements. Which statements successfully swap the contents of the array at index 3 and index 4?
Respuesta
-
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 ];
Pregunta 193
Pregunta
To prevent a class from being instantiated, ________
Respuesta
-
use the static modifier on the constructor.
-
use the public modifier on the constructor.
-
don't use any modifiers on the constructor.
-
use the private modifier on the constructor.
Pregunta 194
Pregunta
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.
Respuesta
-
-p.
-
-a.
-
-d.
-
-dir.
Pregunta 195
Pregunta
An advantage of inheritance is that:
Respuesta
-
All methods can be inherited.
-
All instance variables can be uniformly accessed by subclasses and superclasses.
-
Objects of a subclass can be treated like objects of their superclass.
-
None of the above.
Pregunta 196
Pregunta
An instance of ________ are unchecked exceptions. (Choose all that apply.)
Respuesta
-
Throwable
-
NumberFormatException
-
Error
-
Exception
-
RuntimeException
Pregunta 197
Pregunta
Assume StringBuilder strBuf is "ABCCEFC", after invoking ________, strBuf contains "ABTTEFT".
Respuesta
-
strBuf.replace(2, 7, "TTEFT")
-
strBuf.replace("CC", "TT")
-
strBuf.replace("C", "T")
-
strBuf.replace('C', "TT")
-
strBuf.replace('C', 'T')
Pregunta 198
Pregunta
Using public set methods provides data integrity if:
Respuesta
-
The instance variables are public.
-
The instance variables are private.
-
The methods perform validity checking.
-
Both b and c.
Pregunta 199
Pregunta
Which of the following is the correct header of the main method? (Choose all that apply.)
Respuesta
-
public static void main(String[ ] x)
-
public static void main(String args[ ])
-
static void main(String[ ] args)
-
public static void main(String x[ ])
-
public static void main(String[ ] args)
Pregunta 200
Pregunta
What is x after the following statements?
int x = 1;
int y = 2;
x *= y + 1;
Respuesta
-
x is 2.
-
x is 3.
-
x is 1.
-
x is 4.
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