4147453
Pregunta 1
Pregunta
________is a technical definition of the language that includes the syntax and semantics of the Java programming language.
Respuesta
-
Java JDK
-
Java language specification
-
Java IDE
-
Java API
Pregunta 2
Pregunta
Which JDK command is correct to run a Java application in ByteCode.class?
Respuesta
-
java ByteCode.class
-
javac ByteCode.java
-
javac ByteCode
-
JAVAC ByteCode
-
java ByteCode
Pregunta 3
Pregunta
________ is a software that interprets Java bytecode.
Respuesta
-
Java virtual machine
-
Java API
-
Java compiler
-
Java debugger
Pregunta 4
Pregunta
________ is an operating system.
Respuesta
-
Visual Basic
-
Ada
-
C++
-
Windows XP
-
Java
Pregunta 5
Pregunta
Which of the following are the reserved words? (Choose all that apply.)
Respuesta
-
void
-
class
-
static
-
public
Pregunta 6
Pregunta
________is interpreted.
Respuesta
-
Ada
-
Pascal
-
Java
-
C++
-
C
Pregunta 7
Pregunta
________ contains predefined classes and interfaces for developing Java programs.
Respuesta
-
Java JDK
-
Java API
-
Java language specification
-
Java IDE
Pregunta 8
Pregunta
Which of the following statements is correct?
Respuesta
-
Every line in a program must end with a semicolon.
-
Every comment line must end with a semicolon.
-
Every method must end with a semicolon.
-
Every class must end with a semicolon.
-
Every statement in a program must end with a semicolon.
Pregunta 9
Pregunta
________provides an integrated development environment (IDE) for rapidly developing Java programs. Editing, compiling, building, debugging, and online help are integrated in one graphical user interface.
Respuesta
-
Java JDK
-
Java language specification
-
Java API
-
Java IDE
Pregunta 10
Pregunta
Java was developed by ________.
Respuesta
-
Cisco Systems
-
Sun Microsystems
-
Oracle
-
Microsoft
-
IBM
Pregunta 11
Pregunta
Java compiler translates Java source code into ________.
Respuesta
-
assembly code
-
another high-level language code
-
Java bytecode
-
machine code
Pregunta 12
Pregunta
Suppose you define a Java class as follows:
public class Test {
}
In order to compile this program, the source code should be stored in a file named
Respuesta
-
Test.class
-
Any name with extension .java
-
Test.java
-
Test.doc
-
Test.txt
Pregunta 13
Pregunta
________is Architecture-Neutral.
Respuesta
-
C++
-
Pascal
-
Java
-
Ada
-
C
Pregunta 14
Pregunta
Java ________ can run from a Web browser.
Respuesta
-
servlets
-
Micro Edition programs
-
applets
-
applications
Pregunta 15
Pregunta
________ is the brain of a computer.
Respuesta
-
Disk
-
Memory
-
CPU
-
Hardware
Pregunta 16
Pregunta
The expression "Java " + 1 + 2 + 3 evaluates to ________.
Respuesta
-
Java123
-
java 123
-
Java 123
-
Java6
-
Illegal expression
Pregunta 17
Pregunta
If a program compiles fine, but it produces incorrect result, then the program suffers ________.
Respuesta
-
a compilation error
-
a logic error
-
a runtime error
Pregunta 18
Pregunta
Which of the following code displays the area of a circle if the radius is positive?
Respuesta
-
if (radius <= 0) System.out.println(radius * radius * 3.14159);
-
if (radius >= 0) System.out.println(radius * radius * 3.14159);
-
if (radius > 0) System.out.println(radius * radius * 3.14159);
-
if (radius != 0) System.out.println(radius * radius * 3.14159);
Pregunta 19
Pregunta
What is 1 + 1 + 1 + 1 + 1 == 5?
Respuesta
-
There is no guarantee that 1 + 1 + 1 + 1 + 1 == 5 is true.
-
true
-
false
Pregunta 20
Pregunta
Suppose x is 1. What is x after x += 2?
Respuesta
-
2
-
3
-
1
-
4
-
0
Pregunta 21
Pregunta
Which of the following expression results in a value 1?
Respuesta
-
2 % 1
-
25 % 5
-
15 % 4
-
37 % 6
Pregunta 22
Pregunta
Which of the following are correct names for variables according to Java naming conventions? (Choose all that apply.)
Respuesta
-
FindArea
-
RADIUS
-
Radius
-
findArea
-
radius
Pregunta 23
Pregunta
What is x after the following statements?
int x = 1;
x *= x + 1;
Respuesta
-
x is 2.
-
x is 3.
-
x is 1.
-
x is 4.
Pregunta 24
Pregunta
What is the result of 45 / 4?
Respuesta
-
11
-
11.25
-
12
-
10
Pregunta 25
Pregunta
Analyze the following code:
boolean even = false;
if (even = true) {
System.out.println("It is even!");
}
Respuesta
-
The program has a compile error.
-
The program runs fine and displays It is even!.
-
The program has a runtime error.
-
The program runs fine, but displays nothing.
Pregunta 26
Pregunta
What is i printed in the following code?
public class Test {
public static void main(String[ ] args) {
int j = 0;
int i = j++ + j * 5;
System.out.println("What is i? " + i);
}
}
Respuesta
-
6
-
1
-
5
-
0
Pregunta 27
Pregunta
25 % 1 is ________.
Respuesta
-
3
-
1
-
4
-
2
-
0
Pregunta 28
Pregunta
Analyze the following code. (Choose all that apply.)
int count = 0;
while (count < 100) {
// Point A
System.out.println("Welcome to Java!");
count++;
// Point B
}
// Point C
Respuesta
-
count < 100 is always false at Point C
-
count < 100 is always true at Point A
-
count < 100 is always true at Point C
-
count < 100 is always false at Point B
-
count < 100 is always true at Point B
Pregunta 29
Pregunta
How many times will the following code print "Welcome to Java"?
int count = 0;
while (count < 10) {
System.out.println("Welcome to Java");
count++;
}
Respuesta
-
11
-
9
-
0
-
8
-
10
Pregunta 30
Pregunta
Suppose x is a char variable with a value 'b'. What is the printout of the statement System.out.println(++x)?
Respuesta
-
c
-
a
-
d
-
b
Pregunta 31
Pregunta
Analyze the following code:
Code 1:
boolean even;
if (number % 2 == 0)
even = true;
else
even = false;
Code 2:
boolean even = (number % 2 == 0);
Respuesta
-
Code 2 has compile errors.
-
Both Code 1 and Code 2 have compile errors.
-
Code 1 has compile errors.
-
Both Code 1 and Code 2 are correct, but Code 2 is better.
Pregunta 32
Pregunta
Which of the following is the correct expression that evaluates to true if the number x is between 1 and 100 or the number is negative?
Respuesta
-
1 < x < 100 && x < 0
-
((x < 100) && (x > 1)) || (x < 0)
-
((x < 100) && (x > 1)) && (x < 0)
-
(1 > x > 100) || (x < 0)
Pregunta 33
Pregunta
Suppose x=10 and y=10 what is x after evaluating the expression (y > 10) && (x++ > 10)?
Respuesta
-
9
-
11
-
10
Pregunta 34
Pregunta
What is 1.0 + 1.0 + 1.0 + 1.0 + 1.0 == 5.0?
Respuesta
-
true
-
false
-
There is no guarantee that 1.0 + 1.0 + 1.0 + 1.0 + 1.0 == 5.0 is true.
Pregunta 35
Pregunta
What is the printout of the following switch statement?
char ch = 'a';
switch (ch) {
case 'a':
case 'A':
System.out.print(ch); break;
case 'b':
case 'B':
System.out.print(ch); break;
case 'c':
case 'C':
System.out.print(ch); break;
case 'd':
case 'D':
System.out.print(ch);
}
Respuesta
-
a
-
aa
-
abcd
-
abc
-
ab
Pregunta 36
Pregunta
What is y after the following switch statement is executed?
x = 3;
switch (x + 3) {
case 6: y = 0;
case 7: y = 1;
default: y += 1;
}
Respuesta
-
3
-
1
-
2
-
4
Pregunta 37
Pregunta
Which of the following statements are true? (Choose all that apply.)
Respuesta
-
(x > 0 || x < 10 && y < 0) is same as (x > 0 || (x < 10 && y < 0))
-
(x > 0 || x < 10) is same as ((x > 0) || (x < 10))
-
(x > 0 || x < 10 && y < 0) is same as ((x > 0 || x < 10) && y < 0)
-
(x > 0 && x < 10) is same as ((x > 0) && (x < 10))
Pregunta 38
Pregunta
What is the printout of the following switch statement?
char ch = 'b';
switch (ch) {
case 'a':
System.out.print(ch);
case 'b':
System.out.print(ch);
case 'c':
System.out.print(ch);
case 'd':
System.out.print(ch);
}
Respuesta
-
b
-
bb
-
bcd
-
abcd
-
bbb
Pregunta 39
Pregunta
Analyze the following program fragment:
int x;
double d = 1.5;
switch (d) {
case 1.0: x = 1;
case 1.5: x = 2;
case 2.0: x = 3;
}
Respuesta
-
No errors.
-
The program has a compile error because the required break statement is missing in the switch statement.
-
The switch control variable cannot be double.
-
The program has a compile error because the required default case is missing in the switch statement.
Pregunta 40
Pregunta
Which of the following are valid specifiers for the printf statement? (Choose all that apply.)
Respuesta
-
%6d
-
%10b
-
%4c
-
%8.2d
-
%10.2e
Pregunta 41
Pregunta
Analyze the following code.
boolean even = false;
if (even) {
System.out.println("It is even!");
}
Respuesta
-
The code displays It is even!
-
The code is wrong. You should replace if (even) with if (even = true)
-
The code is wrong. You should replace if (even) with if (even == true)
-
The code displays nothing.
Pregunta 42
Pregunta
Suppose x=10 and y=10. What is x after evaluating the expression (y > 10) && (x-- > 10)?
Respuesta
-
10
-
11
-
9
Pregunta 43
Pregunta
The "less than or equal to" comparison operator in Java is ________.
Respuesta
-
<
-
!=
-
<=
-
=<
-
<<
Pregunta 44
Pregunta
What is the output of the following code?
char ch = 'F';
if (ch >= 'A' && ch <= 'Z')
System.out.println(ch);
Respuesta
-
F
-
f
-
nothing
-
F f
Pregunta 45
Pregunta
________ is the code with natural language mixed with Java code.
Respuesta
-
Pseudocode
-
A Java statement
-
A flowchart diagram
-
Java program
Pregunta 46
Pregunta
The statement System.out.printf("%3.1e", 1234.56) outputs ________.
Respuesta
-
1.23+03
-
1.2e+03
-
0.1e+04
-
0.123456e+04
-
0.123e+04
Pregunta 47
Pregunta
Suppose income is 4001, what is the output of the following code:
if (income > 3000) {
System.out.println("Income is greater than 3000");
}
else if (income > 4000) {
System.out.println("Income is greater than 4000");
Respuesta
-
Income is greater than 3000 followed by Income is greater than 4000
-
Income is greater than 3000
-
Income is greater than 4000 followed by Income is greater than 3000
-
no output
-
Income is greater than 4000
Pregunta 48
Pregunta
Suppose x=10 and y=10 what is x after evaluating the expression (y >= 10) || (x++ > 10)?
Respuesta
-
11
-
10
-
9
Pregunta 49
Pregunta
Analyze the following code fragments that assign a boolean value to the variable even.
Code 1:
if (number % 2 == 0)
even = true;
else
even = false;
Code 2:
even = (number % 2 == 0) ? true: false;
Code 3:
even = number % 2 == 0;
Respuesta
-
All three are correct, but Code 1 is preferred.
-
All three are correct, but Code 3 is preferred.
-
Code 3 has a compile error, because you attempt to assign number to even.
-
Code 2 has a compile error, because you cannot have true and false literals in the conditional expression
-
All three are correct, but Code 2 is preferred.
Pregunta 50
Pregunta
What is the value of the following expression?
true || true && false
Respuesta
-
true
-
false
Pregunta 51
Pregunta
Suppose x = 1, y = -1, and z = 1. What is the printout of the following statement?
if (x > 0)
if (y > 0)
System.out.println("x > 0 and y > 0");
else if (z > 0)
System.out.println("x < 0 and z > 0");
Respuesta
-
x < 0 and z < 0;
-
no printout.
-
x > 0 and y > 0;
-
x < 0 and z > 0;
Pregunta 52
Pregunta
"AbA".compareToIgnoreCase("abC") returns ________.
Respuesta
-
1
-
2
-
-1
-
-2
-
0
Pregunta 53
Pregunta
What is the printout of System.out.println('z' - 'a')?
Respuesta
-
25
-
26
-
a
-
z
Pregunta 54
Pregunta
Assume that the ASCII code for character c is 99 and for a is 97. What is the printout of the following code?
System.out.println('a' + 'c');
Respuesta
-
a99
-
ac
-
9799
-
196
Pregunta 55
Pregunta
Note that the Unicode for character A is 65. The expression "A" + 1 evaluates to ________.
Respuesta
-
66
-
B
-
A1
-
Illegal expression
Pregunta 56
Pregunta
Which of the following method results in 8.0?
Respuesta
-
Math.round(8.5)
-
Math.rint(8.5)
-
Math.ceil(8.5)
-
Math.floor(8.5)
Pregunta 57
Pregunta
The expression 'c' - 'e' is ________.
Respuesta
-
2
-
-2
-
a random number
-
invalid
Pregunta 58
Pregunta
Math.ceil(5.5) evaluates to ________.
Respuesta
-
5.0
-
6.0
-
5
-
6
Pregunta 59
Pregunta
Math.floor(5.5) evaluates to ________.
Respuesta
-
5.0
-
6.0
-
5
-
6
Pregunta 60
Pregunta
To obtain the sine of 35 degrees, use ________.
Respuesta
-
Math.sin(35)
-
Math.sin(Math.toRadians(35))
-
Math.sin(Math.toDegrees(35))
-
Math.sin(Math.toRadian(35))
-
Math.sin(Math.toDegree(35))
Pregunta 61
Pregunta
Which of the following is the correct expression of character a?
Respuesta
-
'a'
-
"a"
-
'\000a'
-
'\a'
Pregunta 62
Pregunta
Math.cos(Math.PI) returns ________.
Respuesta
-
0.0
-
1.0
-
-1.0
-
0.5
Pregunta 63
Pregunta
Which of the following assignment statements is correct?
Respuesta
-
char c = 'd';
-
char c = 100;
-
char c = "d";
-
char c = "100";
Pregunta 64
Pregunta
What is i after the following for loop?
int y = 0;
for (int i = 0; i<10; ++i) {
y += i;
}
Respuesta
-
9
-
undefined
-
10
-
11
Pregunta 65
Pregunta
Which of the following will not help prevent infinite loops?
Respuesta
-
Ensure that the header of a for or while statement is not followed by a semicolon.
-
If the loop is counter-controlled, the body of the loop should increment or decrement the counter as needed.
-
If the loop is sentinel-controlled, ensure that the sentinel value is input eventually.
-
Include braces around the statements in a do..while statement.
Pregunta 66
Pregunta
How many times will the following code print "Welcome to Java"?
int count = 0;
do {
System.out.println("Welcome to Java");
} while (++count < 10);
Respuesta
-
9
-
10
-
0
-
11
-
8
Pregunta 67
Pregunta
For the code segment below:
switch( q )
{
case 1:
System.out.println( "apple" );
break;
case 2:
System.out.println( "orange" );
break;
case 3:
System.out.println( "banana" );
break;
case 4:
System.out.println( "pear" );
case 5:
System.out.println( "grapes" );
default:
System.out.println( "kiwi" );
} // end switch
Which of the following values for q will result in kiwi being included in the output?
Respuesta
-
2
-
3
-
Anything greater than or equal to 4.
-
1
Pregunta 68
Pregunta
Which of the following for-loop control headers results in equivalent numbers of iterations:
A. for ( int q = 1; q <= 100; q++ )
B. for ( int q = 100; q >= 0; q-- )
C. for ( int q = 99; q > 0; q -= 9 )
D. for ( int q = 990; q > 0; q -= 90 )
Respuesta
-
C and D.
-
A and B.
-
None of the loops have equivalent iterations.
-
A and B have equivalent iterations and C and D have equivalent iterations.
Pregunta 69
Pregunta
To exit out of a loop completely, and resume the flow of control at the next line in the method, use _______.
Respuesta
-
A continue statement.
-
A break statement.
-
A return statement.
-
Any of the above.
Pregunta 70
Pregunta
What is the value in count after the following loop is executed?
int count = 0;
do {
System.out.println("Welcome to Java");
} while (count++ < 9);
System.out.println(count);
Respuesta
-
0
-
8
-
9
-
11
-
10
Pregunta 71
Pregunta
What is sum after the following loop terminates?
int sum = 0;
int item = 0;
do {
item++;
sum += item;
if (sum >= 4) continue;
}
while (item < 5);
Respuesta
-
15
-
18
-
17
-
16
Pregunta 72
Pregunta
What is the output for y?
int y = 0;
for (int i = 0; i<10; ++i) {
y += i;
}
System.out.println(y);
Respuesta
-
11
-
13
-
45
-
10
-
12
Pregunta 73
Pregunta
Which of the following is not a type of repetition statement in Java?
Respuesta
-
do¦while statements.
-
for statements.
-
while statements.
-
loop statements.
Pregunta 74
Pregunta
Which of the following statements about the continue statement is true?
Respuesta
-
The continue statement is used to continue after a switch statement.
-
The continue statement is used to exit a repetition structure early and continue execution after the loop.
-
The continue statement does not alter the flow of control.
-
A continue statement proceeds with the next iteration of the immediately enclosing while, for, do¦while statement.
Pregunta 75
Pregunta
Suppose the input for number is 9. What is the output from running the following program?
import java.util.Scanner;
public class Test {
public static void main(String[ ] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter an integer: ");
int number = input.nextInt();
int i;
boolean isPrime = true;
for (i = 2; i < number && isPrime; i++) {
if (number % i == 0) {
isPrime = false;
}
}
System.out.println("i is " + i);
if (isPrime)
System.out.println(number + " is prime");
else
System.out.println(number + " is not prime");
}
}
Respuesta
-
i is 4 followed by 9 is prime
-
i is 3 followed by 9 is not prime
-
i is 3 followed by 9 is prime
-
i is 4 followed by 9 is not prime
Pregunta 76
Pregunta
Analyze the following code: (Choose all that apply.)
public class Test {
public static void main (String args[ ]) {
int i = 0;
for (i = 0; i < 10; i++);
System.out.println(i + 4);
}
}
Respuesta
-
The program has a compile error because of the semicolon (;) on the for loop line.
-
The for loop in this program is same as for (i = 0; i < 10; i++) { }; System.out.println(i + 4);
-
The program compiles despite the semicolon (;) on the for loop line, and displays 14.
-
The program compiles despite the semicolon (;) on the for loop line, and displays 4.
Pregunta 77
Pregunta
The parameter list in the method header and the arguments in the method call must agree in:
Respuesta
-
type
-
number
-
order
-
all the above
Pregunta 78
Pregunta
What is Math.rint(3.5)?
Respuesta
-
5.0
-
4.0
-
3.0
-
3
-
4
Pregunta 79
Pregunta
Which is a correct static method call of Math class method sqrt?
Respuesta
-
Math.sqrt( 900 );.
-
sqrt( 900 );.
-
math.sqrt( 900 );.
-
Math math = new Math(); math.sqrt( 900 );.
Pregunta 80
Pregunta
You can set a Random object's seed at any time during program execution by calling the object's ________ methods.
Respuesta
-
updateSeed.
-
setSeed
-
changeSeed.
-
resetSeed.
Pregunta 81
Pregunta
Identifiers in Java have ________ and ________ scopes?
Respuesta
-
statement, file.
-
class, block.
-
method, class.
-
block, statement.
Pregunta 82
Pregunta
A well-designed method
Respuesta
-
contains thousands of lines of code.
-
performs multiple unrelated tasks.
-
repeats code found in other methods.
-
performs a single, well-defined task.
Pregunta 83
Pregunta
Which of the following methods is not in the Math class?
Respuesta
-
parseInt.
-
abs.
-
ceil.
-
log.
Pregunta 84
Pregunta
Which statement below could be used to simulate the outputs of rolling a six-sided die? Suppose randomNumbers is a Random object.
Respuesta
-
1 + randomNumbers.nextInt( 2 );
-
6 + randomNumbers.nextInt( 1 );
-
3 + randomNumbers.nextInt( 3 );
-
1 + randomNumbers.nextInt( 6 );
Pregunta 85
Pregunta
Which of the following can be an argument to a method?
Respuesta
-
Constants.
-
Variables.
-
Expressions.
-
All of the above.
Pregunta 86
Pregunta
To declare a method as static, place the keyword static before ________ in the method's declaration
Respuesta
-
the return type.
-
the method name.
-
the argument list.
-
the method modifier.
Pregunta 87
Pregunta
Analyze the following code:
public class Test {
public static void main(String[ ] args) {
System.out.println(xMethod(5, 500L));
}
public static int xMethod(int n, long l) {
System.out.println("int, long");
return n;
}
public static long xMethod(long n, long l) {
System.out.println("long, long");
return n;
}
}
Respuesta
-
The program displays int, long followed by 5.
-
The program displays long, long 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 88
Pregunta
Declaring main as ________ allows the JVM to invoke main without creating an instance of the class.
Respuesta
-
void.
-
public.
-
final.
-
static.
Pregunta 89
Pregunta
Variables should be declared as fields only if
Respuesta
-
they are used only within a method.
-
they are local variables.
-
they are required for use in more than one method or their values must be saved between calls to the class's methods.
-
they are arguments.
Pregunta 90
Pregunta
Which of the following methods are overloaded with respect to one another?
A. public int max ( int a, int b ) { … }
B. public double max ( double a, double b ) { … }
C. public int max ( int a, int b, int c ) { … }
D. public double max ( double a, double b, double c ) { … }
Respuesta
-
A and B are overloaded; C and D are overloaded.
-
A and C are overloaded; B and D are overloaded.
-
All these four methods are overloaded.
-
A, B and C are overloaded.
Pregunta 91
Pregunta
The identifiers in an enumeration ________.
Respuesta
-
must be lowercase letters and cannot contain numbers.
-
must be unique.
-
must be uppercase letters and cannot contain numbers.
-
may be duplicated.
Pregunta 92
Pregunta
Analyze the following code.
public class Test {
public static void main(String[ ] args) {
System.out.println(max(1, 2));
}
public static double max(int num1, double num2) {
System.out.println("max(int, double) is invoked");
if (num1 > num2)
return num1;
else
return num2;
}
public static double max(double num1, int num2) {
System.out.println("max(double, int) is invoked");
if (num1 > num2)
return num1;
else
return num2;
}
}
Respuesta
-
The program cannot compile because the compiler cannot determine which max method should be invoked.
-
The program runs and prints 2 followed by "max(int, double)" is invoked.
-
The program cannot compile because you cannot have the print statement in a non-void method.
-
The program runs and prints "max(int, double) is invoked" followed by 2.
-
The program runs and prints 2 followed by "max(double, int)" is invoked.
Pregunta 93
Pregunta
What is Math.floor(3.6)?
Respuesta
-
3.0
-
5.0
-
4
-
3
Pregunta 94
Pregunta
What is Math.round(3.6)?
Respuesta
-
3.0
-
3
-
4
-
4.0
Pregunta 95
Pregunta
(int)('a' + Math.random() * ('z' - 'a' + 1)) returns a random number ________.
Respuesta
-
between 'a' and 'z'
-
between (int)'a' and (int)'z'
-
between 0 and (int)'z'
-
between 'a' and 'y'
Pregunta 96
Pregunta
Given the following method
static void nPrint(String message, int n) {
while (n > 0) {
System.out.print(message);
n--;
}
}
What is k after invoking nPrint("A message", k)?
int k = 2;
nPrint("A message", k);
Respuesta
-
3
-
0
-
1
-
2
Pregunta 97
Pregunta
Does the method call in the following method cause compile errors?
public static void main(String[ ] args) {
Math.pow(2, 4);
}
Respuesta
-
Yes
-
No
Pregunta 98
Pregunta
Method calls cannot be distinguished by ________.
Respuesta
-
return type.
-
method name.
-
method signature.`
-
parameter lists.
Pregunta 99
Pregunta
________ is to implement one method in the structure chart at a time from the top to the bottom.
Respuesta
-
Bottom-up approach
-
Stepwise refinement
-
Bottom-up and top-down approach
-
Top-down approach
Pregunta 100
Pregunta
Which of the following is a possible output from invoking Math.random()? (Choose all that apply.)
Respuesta
-
3.43
-
0.0
-
1.0
-
0.5
Pregunta 101
Pregunta
Which statement below could be used to simulate the outputs of tossing a quarter to get heads or tails? Suppose randomNumbers is a Random object.
Respuesta
-
randomNumbers.nextInt( 7 );
-
randomNumbers.nextInt( 1 );
-
randomNumbers.nextInt( 2 );
-
randomNumbers.nextInt( 25 );
Pregunta 102
Pregunta
A Java class can have which of the following methods?
A. void foo( int a )
B. void foo( int a, int b )
C. void foo( double a )
D. void foo( double a, double b )
E. void foo( int b )
Respuesta
-
A, B, C, D.
-
All of the above.
-
A, C, D, E.
-
A, B, D, E.
Pregunta 103
Pregunta
If more method calls occur than can have their activation records stored on the program execution stack, an error known as a ________ occurs.
Respuesta
-
stack empty.
-
stack overflow.
-
stack full.
-
stack rewind.
Pregunta 104
Pregunta
Which statement creates a random value from the sequence 2, 5, 8, 11 and 14. Suppose randomNumbers is a Random object.
Respuesta
-
3 + 2 * randomNumbers.nextInt( 5 );
-
5 + 3 * randomNumbers.nextInt( 2 );
-
2 + 3 * randomNumbers.nextInt( 5 );
-
2 + 5 * randomNumbers.nextInt( 3 );
Pregunta 105
Pregunta
Analyze the following code:
public class Test {
public static void main(String[ ] args) {
final 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 0 0
-
The program displays 1 2 3 4
-
The program has a compile error on the statement x = new int[2], because x is final and cannot be changed.
-
The elements in the array x cannot be changed, because x is final.
Pregunta 106
Pregunta
For the binarySearch method in Section 6.9.2, what is low and high after the first iteration of the while loop when invoking binarySearch(new int[ ]{1, 4, 6, 8, 10, 15, 20}, 11)?
Respuesta
-
low is 3 and high is 6
-
low is 0 and high is 5
-
low is 4 and high is 6
-
low is 0 and high is 6
-
low is 0 and high is 3
Pregunta 107
Pregunta
Analyze the following code.
public class Test {
public static void main(String[ ] args) {
int[ ] x = new int[3];
System.out.println("x[0] is " + x[0]);
}
}
Respuesta
-
The program has a runtime error because the array element x[0] is not defined.
-
The program runs fine and displays x[0] is 0.
-
The program has a compile error because the size of the array wasn't specified when declaring the array.
-
The program has a runtime error because the array elements are not initialized.
Pregunta 108
Pregunta
Assume int[ ] scores = {1, 20, 30, 40, 50}, what value does java.util.Arrays.binarySearch(scores, 30) return?
Respuesta
-
1
-
-1
-
2
-
-2
-
0
Pregunta 109
Pregunta
Analyze the following code:
public class Test {
public static void main(String[ ] args) {
int[ ] x = new int[5];
int i;
for (i = 0; i < x.length; i++)
x[i] = i;
System.out.println(x[i]);
}
}
Respuesta
-
The program has a compile error because i is not defined in the last statement in the main method.
-
The program has a runtime error because the last statement in the main method causes ArrayIndexOutOfBoundsException.
-
The program displays 4.
-
The program displays 0 1 2 3 4.
Pregunta 110
Pregunta
The reverse method is defined in the textbook. What is list1 after executing the following statements?
int[ ] list1 = {1, 2, 3, 4, 5, 6};
list1 = reverse(list1);
Respuesta
-
list1 is 6 5 4 3 2 1
-
list1 is 0 0 0 0 0 0
-
list1 is 1 2 3 4 5 6
-
list1 is 6 6 6 6 6 6
Pregunta 111
Pregunta
What would be the result of attempting to compile and run the following code?
public class Test {
public static void main(String[ ] args) {
double[ ] x = new double[ ]{1, 2, 3};
System.out.println("Value is " + x[1]);
}
}
Respuesta
-
The program has a compile error because the syntax new double[ ]{1, 2, 3} is wrong and it should be replaced by new double[ ]{1.0, 2.0, 3.0};
-
The program compiles and runs fine and the output "Value is 1.0" is printed.
-
The program compiles and runs fine and the output "Value is 2.0" is printed.
-
The program has a compile error because the syntax new double[ ]{1, 2, 3} is wrong and it should be replaced by new double[3]{1, 2, 3};
-
The program has a compile error because the syntax new double[ ]{1, 2, 3} is wrong and it should be replaced by {1, 2, 3}.
Pregunta 112
Pregunta
Do the following two programs produce the same result?
Program I:
public class Test {
public static void main(String[ ] args) {
int[ ] list = {1, 2, 3, 4, 5};
reverse(list);
for (int i = 0; i < list.length; i++)
System.out.print(list[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;
}
}
Program II:
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
-
Yes
-
No
Pregunta 113
Pregunta
Which of the following statements is valid? (Choose all that apply.)
Respuesta
-
int[ ] i = {3, 4, 3, 2};
-
char[ ] c = new char();
-
int i = new int(30);
-
char[ ] c = new char[4]{'a', 'b', 'c', 'd'};
-
double d[ ] = new double[30];
Pregunta 114
Pregunta
The selectionSort method is defined in this section. What is list1 after executing the following statements?
double[ ] list1 = {3.1, 3.1, 2.5, 6.4};
selectionSort(list1);
Respuesta
-
list1 is 3.1, 2.5, 3.1, 6.4
-
list1 is 3.1, 3.1, 2.5, 6.4
-
list1 is 2.5 3.1, 3.1, 6.4
-
list1 is 6.4, 3.1, 3.1, 2.5
Pregunta 115
Pregunta
If a key is not in the list, the binarySearch method returns ________.
Respuesta
-
-(insertion point + 1)
-
-insertion point
-
insertion point - 1
-
insertion point
Pregunta 116
Pregunta
How can you initialize an array of two characters to 'a' and 'b'? (Choose all that apply.)
Respuesta
-
char[2] charArray = {'a', 'b'};
-
char[ ] charArray = new char[2]; charArray = {'a', 'b'};
-
char[ ] charArray = new char[ ]{'a', 'b'};
-
char[ ] charArray = {'a', 'b'};
Pregunta 117
Pregunta
What is the correct term for numbers[99]?
Respuesta
-
array
-
array variable
-
indexed variable
-
index
-
index variable
Pregunta 118
Pregunta
If you declare an array double[ ] list = {3.4, 2.0, 3.5, 5.5}, list[1] is ________.
Respuesta
-
3.4
-
5.5
-
2.0
-
undefined
Pregunta 119
Pregunta
The ________ method sorts the array scores of the double[ ] type.
Respuesta
-
java.util.Arrays.sort(scores)
-
java.util.Arrays(scores)
-
java.util.Arrays.sorts(scores)
-
Njava.util.Arrays.sortArray(scores)
Pregunta 120
Pregunta
Which of the following is incorrect? (Choose all that apply.)
Respuesta
-
int a = new int[2];
-
int[ ] a = new int[2];
-
int a() = new int[2];
-
int[ ] a = new int(2);
-
int a[ ] = new int[2];
Pregunta 121
Pregunta
Which of the following statements are correct? (Choose all that apply.)
Respuesta
-
char[ ][ ][ ] charArray = new char[2][2][ ];
-
char[ ][ ][ ] charArray = {{{'a', 'b'}, {'c', 'd'}, {'e', 'f'}}};
-
char[2][2][ ] charArray = {'a', 'b'};
-
char[ ][ ][ ] charArray = {{'a', 'b'}, {'c', 'd'}, {'e', 'f'}};
Pregunta 122
Pregunta
Assume double[ ][ ] x = new double[4][5], what are x.length and x[2].length?
Respuesta
-
4 and 5
-
5 and 5
-
5 and 4
-
4 and 4
Pregunta 123
Pregunta
Suppose a method p has the following heading:
public static int[ ][ ] p()
What return statement may be used in p()?
Respuesta
-
return {1, 2, 3};
-
return 1;
-
return new int[ ]{1, 2, 3};
-
return int[ ]{1, 2, 3};
-
return new int[ ][ ]{{1, 2, 3}, {2, 4, 5}};
Pregunta 124
Pregunta
Assume int[ ] scores = {1, 20, 30, 40, 50}, what value does java.util.Arrays.binarySearch(scores, 3) return?
Respuesta
-
1
-
-2
-
2
-
0
-
-1
Pregunta 125
Pregunta
What is the representation of the third element in an array called a?
Respuesta
-
a(3)
-
a(2)
-
a[2]
-
a[3]
Pregunta 126
Pregunta
Which of the following statements are correct?
Respuesta
-
char[2][ ] charArray = {{'a', 'b'}, {'c', 'd'}};
-
char[ ][ ] charArray = {{'a', 'b'}, {'c', 'd'}};
-
char[ ][ ] charArray = {'a', 'b'};
-
char[2][2] charArray = {{'a', 'b'}, {'c', 'd'}};
Pregunta 127
Pregunta
Assume double[ ][ ][ ] x = new double[4][5][6], what are x.length, x[2].length, and x[0][0].length?
Respuesta
-
4, 5, and 6
-
5, 5, and 5
-
4, 5, and 4
-
6, 5, and 4
Pregunta 128
Pregunta
Analyze the following code:
public class Test {
public static void main(String[ ] args) {
boolean[ ][ ] x = new boolean[3][ ];
x[0] = new boolean[1]; x[1] = new boolean[2];
x[2] = new boolean[3];
System.out.println("x[2][2] is " + x[2][2]);
}
}
Respuesta
-
The program has a runtime error because x[2][2] is null.
-
The program runs and displays x[2][2] is false.
-
The program has a compile error because new boolean[3][ ] is wrong.
-
The program runs and displays x[2][2] is true.
-
The program runs and displays x[2][2] is null.
Pregunta 129
Pregunta
Which of the following statements are correct to invoke the printMax method in Listing 6.5 in the textbook? (Choose all that apply.)
Respuesta
-
printMax(1.0, 2.0, 2.0, 1.0, 4.0);
-
printMax(new double[ ]{1, 2, 3});
-
printMax(1, 2, 2, 1, 4);
-
printMax(new int[ ]{1, 2, 3});
Pregunta 130
Pregunta
In the following code, what is the printout for list2?
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 < list2.length; i++)
System.out.print(list2[i] + " ");
}
}
Respuesta
-
0 1 2
-
1 1 1
-
1 2 3
-
0 1 3
Pregunta 131
Pregunta
Which of the following errors is synchronous?
Respuesta
-
All of the above.
-
Unsuccessful memory allocation.
-
Arithmetic overflow.
-
Divide by zero.
Pregunta 132
Pregunta
When an unchecked exception occurs in a method but is not caught:
Respuesta
-
all local variables in that method go out of scope.
-
the method terminates.
-
All of the above.
-
the method-call stack is unwound.
Pregunta 133
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;
double y = 2.0 / i;
System.out.println("Welcome to HTML");
}
finally {
System.out.println("The finally clause is executed");
}
}
}
Respuesta
-
Welcome to Java.
-
The program displays three lines: Welcome to Java, Welcome to HTML, The finally clause is executed.
-
None of the above.
-
Welcome to Java followed by The finally clause is executed in the next line.
Pregunta 134
Pregunta
What exception type does the following program throw?
public class Test {
public static void main(String[ ] args) {
String s = "abc";
System.out.println(s.charAt(3));
}
}
Respuesta
-
ArrayIndexOutOfBoundsException
-
No exception
-
StringIndexOutOfBoundsException
-
ArithmeticException
-
ClassCastException
Pregunta 135
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 Java");
}
catch (RuntimeException ex) {
System.out.println("Welcome to Java");
}
finally {
System.out.println("End of the block");
}
}
}
Respuesta
-
The program displays Welcome to Java three times followed by End of the block.
-
The program displays Welcome to Java three times.
-
The program displays Welcome to Java two times.
-
The program displays Welcome to Java two times followed by End of the block.
Pregunta 136
Pregunta
What is displayed on the console when running the following program?
class Test {
public static void main(String[ ] args) {
try {
method();
System.out.println("After the method call");
}
catch (RuntimeException ex) {
System.out.println("RuntimeException");
}
catch (Exception ex) {
System.out.println("Exception");
}
}
static void method() throws Exception {
try {
String s = "5.6";
Integer.parseInt(s); // Cause a NumberFormatException
int i = 0;
int y = 2 / i;
System.out.println("Welcome to Java");
}
catch (NumberFormatException ex) {
System.out.println("NumberFormatException");
throw ex;
}
catch (RuntimeException ex) {
System.out.println("RuntimeException");
}
}
}
Respuesta
-
The program has a compilation error.
-
The program displays NumberFormatException twice.
-
The program displays NumberFormatException followed by RuntimeException.
-
The program displays NumberFormatException followed by After the method call.
Pregunta 137
Pregunta
Which of the following statements is false?
Respuesta
-
The class Throwable provides the method getMessage that returns the descriptive string stored in an exception.
-
The string returned from class Throwable’s getMessage method contains the name of the exception’s class.
-
The class Throwable provides the method getStackTrace that outputs the stack trace to the standard error stream.
-
All exceptions must derive from the class Throwable.
Pregunta 138
Pregunta
Analyze the following code:
class Test {
public static void main(String[ ] args) {
try {
int zero = 0;
int y = 2/zero;
try {
String s = "5.6";
Integer.parseInt(s); // Cause a NumberFormatException
}
catch(Exception e) {
}
}
catch(RuntimeException e) {
System.out.println(e);
}
}
}
Respuesta
-
The program has a compilation error because Exception appears before RuntimeException.
-
A try-catch block cannot be embedded inside another try-catch block.
-
A good programming practice is to avoid nesting try-catch blocks, because nesting makes programs difficult to read. You can rewrite the program using only one try-catch block.
-
None of the above.
Pregunta 139
Pregunta
To catch an exception, the code that might throw the exception must be enclosed in a
Respuesta
-
try block.
-
catch block.
-
throws block.
-
finally block.
Pregunta 140
Pregunta
An uncaught exception:
Respuesta
-
is a possible exception that never actually occurs during the execution of the program.
-
is an exception that occurs for which the matching catch clause is empty.
-
is an exception that occurs for which there are no matching catch clauses.
-
is another term for a thrown exception.
Pregunta 141
Pregunta
What exception type does the following program throw?
public class Test {
public static void main(String[ ] args) {
int[ ] list = new int[5];
System.out.println(list[5]);
}
}
Respuesta
-
ClassCastException
-
ArrayIndexOutOfBoundsException
-
No exception
-
ArithmeticException
-
StringIndexOutOfBoundsException
Pregunta 142
Pregunta
After a finally block has finished executing (and there are no exceptions to be handled):
Respuesta
-
control returns to the throw point.
-
the application exits.
-
control proceeds to the first statement after the finally block.
-
control proceeds to the first statement after the last catch block.
Pregunta 143
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 Java");
}
finally {
System.out.println("End of the block");
}
System.out.println("End of the block");
}
}
Respuesta
-
The program displays Welcome to Java two times followed by End of the block two times.
-
The program displays Welcome to Java two times followed by End of the block.
-
The program displays Welcome to Java three times followed by End of the block.
-
The program displays Welcome to Java and End of the block, and then terminates because of an unhandled exception.
Pregunta 144
Pregunta
Which of the following is not included in an exception's stack trace?
Respuesta
-
Instructions on handling the exception.
-
A descriptive message for the exception.
-
The method-call stack at the time the exception occurred.
-
The name of the exception.
Pregunta 145
Pregunta
Which of the following statements is false?
Respuesta
-
The finally block and try block can appear in any order.
-
A finally block is placed after the last catch block.
-
A finally block typically releases resources acquired in the corresponding try block.
-
A finally block is optional.
Pregunta 146
Pregunta
Attributes of a class are also known as:
Respuesta
-
Constructors.
-
Fields.
-
Local variables.
-
Classes.
Pregunta 147
Pregunta
________ is invoked to create an object.
Respuesta
-
A method with the void return type
-
A method with a return type
-
The main method
-
A constructor
Pregunta 148
Pregunta
What type of methods allow a client of a class to assign values to a private instance variable?
Respuesta
-
Assign methods.
-
Replace methods.
-
Get methods.
-
Set methods.
Pregunta 149
Pregunta
Which of the following statement is most accurate? (Choose all that apply.)
Respuesta
-
A reference variable refers to an object.
-
An object may contain the references of other objects.
-
A reference variable is an object.
-
An object may contain other objects.
Pregunta 150
Pregunta
What is the value of myCount.count displayed?
public class Test {
public static void main(String[ ] args) {
Count myCount = new Count();
int times = 0;
for (int i=0; i<100; i++)
increment(myCount, times);
System.out.println(
"myCount.count = " + myCount.count);
System.out.println("times = "+ times);
}
public static void increment(Count c, int times) {
c.count++;
times++;
}
}
class Count {
int count;
Count(int c) {
count = c;
}
Count() {
count = 1;
}
}
Respuesta
-
98
-
99
-
100
-
101
Pregunta 151
Pregunta
Suppose you wish to provide an accessor method for a boolean property finished, what signature of the method should be?
Respuesta
-
public void getFinished()
-
public boolean getFinished()
-
public boolean isFinished()
-
public void isFinished()
Pregunta 152
Pregunta
What is the printout of the third 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
-
f3.i is 1 f3.s is 1
-
f3.i is 3 f3.s is 3
-
f3.i is 3 f3.s is 1
-
f3.i is 1 f3.s is 2
-
f3.i is 1 f3.s is 3
Pregunta 153
Pregunta
Sending a message to an object means that:
Respuesta
-
Neither (a) nor (b).
-
You access a variable of the object.
-
You call a method of the object.
-
Both (a) and (b).
Pregunta 154
Pregunta
Analyze the following code and choose the best answer:
public class Foo {
private int x;
public static void main(String[ ] args) {
Foo foo = new Foo();
System.out.println(foo.x);
}
}
Respuesta
-
Since x is an instance variable, it cannot be directly used inside a main method. However, it can be accessed through an object such as foo in this code.
-
Since x is private, it cannot be accessed from an object foo.
-
You cannot create a self-referenced object; that is, foo is created inside the class Foo.
-
Since x is defined in the class Foo, it can be accessed by any method inside the class without using an object. You can write the code to access x without creating an object such as foo in this code.
Pregunta 155
Pregunta
Analyze the following code:
public class Test {
public static void main(String[ ] args) {
double radius;
final double PI= 3.15169;
double area = radius * radius * PI;
System.out.println("Area is " + area);
}
}
Respuesta
-
The program has compile errors because the variable radius is not initialized.
-
The program compiles and runs fine.
-
The program has no compile errors but will get a runtime error because radius is not initialized.
-
The program has a compile error because a constant PI is defined inside a method.
Pregunta 156
Pregunta
Analyze the following code:
public class Test {
private int t;
public static void main(String[ ] args) {
int x;
System.out.println(t);
}
}
Respuesta
-
The program compiles and runs fine.
-
t is non-static and it cannot be referenced in a static context in the main method.
-
The variable x is not initialized and therefore causes errors.
-
The variable t is private and therefore cannot be accessed in the main method.
-
The variable t is not initialized and therefore causes errors.
Pregunta 157
Pregunta
Analyze the following code:
public class Test {
public static void main(String args[ ]) {
NClass nc = new NClass();
nc.t = nc.t++;
}
}
class NClass {
int t;
private NClass() {
}
}
Respuesta
-
The program has a compilation error because the NClass class has a private constructor.
-
The program compiles and runs fine.
-
The program does not compile because the parameter list of the main method is wrong.
-
The program compiles, but has a runtime error because t has no initial value.
Pregunta 158
Pregunta
A method that is associated with an individual object is called ________.
Respuesta
-
an object method
-
a static method
-
a class method
-
an instance method
Pregunta 159
Pregunta
When invoking a method with an object argument, ________ is passed.
Respuesta
-
the contents of the object
-
a copy of the object
-
the reference of the object
-
the object is copied, then the reference of the copied object
Pregunta 160
Pregunta
Which of the following statements are true? (Choose all that apply.)
Respuesta
-
Use the private modifier to encapsulate data fields.
-
Encapsulating data fields helps prevent programming errors.
-
Encapsulating data fields makes the program easy to maintain.
-
Encapsulating data fields makes the program short.
Pregunta 161
Pregunta
What is the printout for the first 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
-
i + j is 23
-
i + j is 22
-
i + j is 5
-
i + j is 6
Pregunta 162
Pregunta
In the UML, a class's attributes are placed in the ________ compartment of the class's rectangle.
Respuesta
-
third
-
second
-
bottom
-
first
Pregunta 163
Pregunta
You can declare two variables with the same name in ________.
Respuesta
-
different methods in a class
-
a method one as a formal parameter and the other as a local variable
-
two nested blocks in a method (two nested blocks means one being inside the other)
-
a block
Pregunta 164
Pregunta
We can derive many of the operations of each class by examining the key ________ and ________ in the requirements documents.
Respuesta
-
nouns. noun phrases.
-
objectives, objective phrases.
-
verbs, verb phrases.
-
Both a and b.
Pregunta 165
Pregunta
The sequence of messages in a communication diagram progresses:
Respuesta
-
alphabetically.
-
None of the above.
-
in numerical order from least to greatest.
-
Both of the above.
Pregunta 166
Pregunta
Objects are modeled in the UML as         containing names in the form         .
Respuesta
-
rectangles, : ClassName.
-
rectangles, objectName : ClassName.
-
ovals, objectName : ClassName.
-
ovals, : ClassName.
Pregunta 167
Pregunta
In the UML, the         diagram emphasizes which objects participate in collaborations.
Respuesta
-
collaboration.
-
participation.
-
sequence.
-
communication.
Pregunta 168
Pregunta
UML ________ model several states of an object and show under what circumstances the object changes state.
Respuesta
-
diagrams.
-
state machine diagrams.
-
machine diagrams.
-
activity diagrams.
Pregunta 169
Pregunta
What is the printout for the second 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
-
k is 0
-
k is 1
-
k is 3
-
k is 2
Pregunta 170
Pregunta
Which diagram is also called a collaboration diagram.
Respuesta
-
State machine diagram.
-
Sequence diagram.
-
Activity diagram.
-
Communication diagram.
Pregunta 171
Pregunta
Analyze the following code: (Choose all that apply.)
class Test {
private double i;
public Test(double i) {
this.t();
this.i = i;
}
public Test() {
System.out.println("Default constructor");
this(1);
}
public void t() {
System.out.println("Invoking t");
}
}
Respuesta
-
this(1) must be replaced by this(1.0).
-
this.i may be replaced by i.
-
this(1) must be called before System.out.println("Default constructor").
-
this.t() may be replaced by t().
Pregunta 172
Pregunta
What is a message between collaborating objects called in the UML?
Respuesta
-
communication call.
-
collaboration call.
-
synchronous call.
-
asynchronous call.
Pregunta 173
Pregunta
Communication diagrams contain an object's lifeline. Which of the following is true of the object's lifeline?
Respuesta
-
Actions occur along an object's lifeline in chronological order from top to bottom.
-
The lifeline represents the progression of time.
-
All of the above are true.
-
The line is dotted.
Pregunta 174
Pregunta
An activation indicates that:
Respuesta
-
an object is sending a message.
-
an object is being created.
-
an object has completed executing.
-
an object is executing.
Pregunta 175
Pregunta
The use case diagram models ________.
Respuesta
-
each software life cycle by repeating one or more stages several times via use cases.
-
each software life cycle stage in succession.
-
the interactions between implementations and testing.
-
the interactions between a system's client and one of the system's capabilities.
Pregunta 176
Pregunta
Which of the following statements are true? (Choose all that apply.)
Respuesta
-
Dynamic binding can apply to static methods.
-
The compiler finds a matching method according to parameter type, number of parameters, and order of the parameters at compilation time.
-
A method may be implemented in several subclasses. The Java Virtual Machine dynamically binds the implementation of the method at runtime.
-
You can always pass an instance of a subclass to a parameter of its superclass type. This feature is known as polymorphism.
-
Dynamic binding can apply to instance methods.
Pregunta 177
Pregunta
Which method changes the text the label displays?
Respuesta
-
changeText.
-
changeLabel.
-
setLabel.
-
setText.
Pregunta 178
Pregunta
Composition means ________.
Respuesta
-
that a class can extend another class
-
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
Pregunta 179
Pregunta
Every object in Java knows its own class and can access this information through method ___________________ .
Respuesta
-
getClass.
-
objectInformation.
-
getInformation.
-
objectClass.
Pregunta 180
Pregunta
Analyze the following code: (Choose all that apply.)
import java.util.StringTokenizer;
public class A extends StringTokenizer {
}
Respuesta
-
The program would compile fine if you add the following constructor into A: A(String s) { super(s); }
-
The program has a compilation error because A does not have a default constructor.
-
The program would compile fine if you add the following constructor into A: A(String s) { }
-
The program has a compilation error because the default constructor of A invokes the default constructor of StringTokenizer, but StringTokenizer does not have a default constructor.
Pregunta 181
Pregunta
The default implementation of method clone of Object performs a ________.
Respuesta
-
full copy.
-
shallow copy.
-
empty copy.
-
deep copy.
Pregunta 182
Pregunta
Analyze the following code:
public class Test {
public static void main(String[ ] args) {
String s = new String("Welcome to Java");
Object o = s;
String d = (String)o;
}
}
Respuesta
-
When casting o to s in String d = (String)o, a new object is created.
-
When assigning s to o in Object o = s, a new object is created.
-
When casting o to s in String d = (String)o, the contents of o is changed.
-
s, o, and d reference the same String object.
Pregunta 183
Pregunta
Inheritance is also known as the
Respuesta
-
"is-a" relationship.
-
"knows-a" relationship.
-
"uses-a" relationship.
-
"has-a" relationship.
Pregunta 184
Pregunta
Polymorphism enables you to:
Respuesta
-
program in the general.
-
hide information from the user.
-
program in the specific.
-
absorb attributes and behavior from previous classes.
Pregunta 185
Pregunta
Which of the following statements are true? (Choose all that apply.)
Respuesta
-
"class A extends B" means B is a subclass of A.
-
"class A extends B" means A is a subclass of B.
-
A subclass is a subset of a superclass.
-
A subclass is usually extended to contain more functions and more detailed information than its superclass.
Pregunta 186
Pregunta
Classes and methods are declared final for all but the following reasons:
Respuesta
-
final methods allow inlining the code.
-
final methods can improve performance.
-
final methods are static.
-
final methods and classes prevent further inheritance.
Pregunta 187
Pregunta
When a superclass variable refers to a subclass object and a method is called on that object, the proper implementation is determined at execution time. What is the process of determining the correct method to call?
Respuesta
-
execution binding.
-
execution time binding.
-
just-in-time binding.
-
late binding.
Pregunta 188
Pregunta
Which of the following is the superclass constructor call syntax?
Respuesta
-
keyword super, followed by a dot (.) .
-
keyword super, followed by a dot and the superclass constructor name.
-
None of the above.
-
keyword super, followed by a set of parentheses containing the superclass constructor arguments.
Pregunta 189
Pregunta
Which of the statements regarding the super keyword is incorrect?
Respuesta
-
You can use super to invoke a super class method.
-
You can use super to invoke a super class constructor.
-
You can use super.super.p to invoke a method in superclass's parent class.
-
You cannot invoke a method in superclass's parent class.
Pregunta 190
Pregunta
Which statement best describes the relationship between superclass and subclass types?
Respuesta
-
A subclass reference can be assigned to a superclass variable, but a superclass reference cannot be assigned to a subclass variable.
-
A superclass reference can be assigned to a subclass variable, but a subclass reference cannot be assigned to a superclass variable.
-
A subclass reference can be assigned to a superclass variable and a superclass reference can be assigned to a subclass variable.
-
A subclass reference cannot be assigned to a superclass variable and a superclass reference cannot be assigned to a subclass variable.
Pregunta 191
Pregunta
A Java character is stored in ________.
Respuesta
-
two bytes
-
four bytes
-
one byte
-
three bytes
Pregunta 192
Pregunta
Which statement is false?
Respuesta
-
Unless directed otherwise, the computer executes Java statements one after the other in the order in which they are written.
-
Activity diagrams normally show the Java code that implements the activity.
-
Like pseudocode, activity diagrams help programmers develop and represent algorithms.
-
The arrows in the activity diagram represent transitions, which indicate the order in which the actions represented by the action states occur.
Pregunta 193
Pregunta
Keyword ________ indicates the inheritance relationship.
Respuesta
-
extends
-
inherits
-
super
-
parent
Pregunta 194
Pregunta
What is the result value of c at the end of the following code segment?
int c = 8;
c++;
++c;
c %= 5;
Respuesta
-
0.
-
1.
-
3.
-
None of the above.
Pregunta 195
Pregunta
Which statement is false?
Respuesta
-
To ensure that the operands are of the same type, Java performs implicit conversion on selected operands.
-
Cast operators are unary operators.
-
Cast operators associate from right to left and are one level lower in precedence than the multiplicative operators.
-
Cast operators are formed by placing parentheses around the name of a type.
Pregunta 196
Pregunta
Which of the following would not be used to clarify a dangling-else?
Respuesta
-
Indentation.
-
Parentheses ().
-
Braces {}.
-
Comment //.
Pregunta 197
Pregunta
To assign a double variable d to a float variable x, you write
Respuesta
-
x = (long)d
-
x = d;
-
x = (float)d;
-
x = (int)d;
Pregunta 198
Pregunta
Suppose i is an int type variable. Which of the following statements display the character whose Unicode is stored in variable i?
Respuesta
-
System.out.println(i);
-
System.out.println(i + " ");
-
System.out.println((int)i);
-
System.out.println((char)i);
Pregunta 199
Pregunta
What is the number of iterations in the following loop:
for (int i = 1; i < n; i++) {
// iteration
}
Respuesta
-
n - 1
-
n
-
n + 1
-
2*n
Pregunta 200
Pregunta
Consider the following Java statements:
int x = 9;
double y = 5.3;
result = calculateValue( x, y );
Respuesta
-
A method is called with its name and parentheses.
-
x and y are parameters.
-
Copies of x and y are passed to the method calculateValue().
-
x and y are arguments.
¿Quieres crear tus propios Tests gratis con GoConqr? Más información.