Question 1
Question
Which class do you use to write data into a text file?
Answer
-
System
-
PrintWriter
-
Scanner
-
File
Question 2
Question
Which of the following statements is false?
Answer
-
The smallest data item a computer can assume is the value 0 or the value 1.
-
The term "bit" is short for "byte digit."
-
Java uses the Unicode character set.
-
A record is typically composed of several fields.
Question 3
Question
What is the return value of "SELECT".substring(0, 5)?
Answer
-
"SELECT"
-
"SELE"
-
"SELEC"
-
"ELECT"
Question 4
Question
Which of the following assignment statements is incorrect? (Choose all that apply.)
Answer
-
i == j == k == 1;
-
i = j = k = 1;
-
i = 1; j = 1; k = 1;
-
i = 1 = j = 1 = k = 1;
Question 5
Question
An argument type followed by a(n) __________________ in a method's parameter list indicates that the method receives a variable number of arguments of that particular type.
Question 6
Question
Which of the following statements creates a multidimensional array with 3 rows, where the first row contains 1 element, the second row contains 4 elements and the final row contains 2 elements?
Answer
-
int[][] items = { { 1, null, null, null }, { 2, 3, 4, 5 }, { 6, 7, null, null } };.
-
int[][] items = { { 1 }, { 2, 3, 4, 5 }, { 6, 7 } };.
-
int[][] items = { { 1 }, { 2, 3, 4, 5 }, { 6, 7 }, {} );.
-
int[][] items = { { 1 }, { 4 }, { 2 } };.
Question 7
Question
What modifier should you use on the members of a class so that they are not accessible to another class in a different package, but are accessible to any subclasses in any package?
Question 8
Question
Which of the following statements are true about an immutable object? (Choose all that apply.)
Answer
-
The contents of an immutable object cannot be modified.
-
An immutable object contains no mutator methods.
-
All properties of an immutable object must be of primitive types.
-
All properties of an immutable object must be private.
-
An object type property in an immutable object must also be immutable.
Question 9
Question
What is the output of the following code?
public class Test {
public static void main(String[ ] args) {
String s1 = new String("Welcome to Java");
String s2 = s1;
s1 += "and Welcome to HTML";
if (s1 == s2)
System.out.println("s1 and s2 reference to the same String object");
else
System.out.println("s1 and s2 reference to different String objects");
}
}
Question 10
Question
Which of the following is not an algorithm?
Question 11
Question
Which of the following segments is a proper way to call the method readData four times?
Answer
-
double k;
k = 0.0;
while (k != 4)
{
readData();
k = k + 1;
} // end while
-
int i;
i = 0;
while ( i <= 4 )
{
readData();
i = i + 1;
} // end while
-
int i;
i = 0;
while ( i < 4 )
{
readData();
} // end while
-
int i;
i = 0;
while ( i < 4 )
{
readData();
i = i + 1;
} // end while
Question 12
Question
Which method returns an array of the enum’s constants?
Answer
-
values.
-
getValues.
-
constants.
-
getConstants.
Question 13
Question
An anonymous String:
Answer
-
has no value.
-
is a string literal.
-
can be changed.
-
none of the above.
Question 14
Question
What exception type does the following program throw?
public class Test {
public static void main(String[ ] args) {
Object o = null;
System.out.println(o);
}
}
Question 15
Question
Overloaded methods always have the same _________.
Answer
-
method name.
-
return type.
-
number of parameters.
-
order of the parameters.
Question 16
Question
All import declarations must be placed
Answer
-
inside the class declaration’s body.
-
before the class declaration.
-
after the class declaration.
-
all of the above will work.
Question 17
Question
The preferred way to traverse a two-dimensional array is to use _______ .
Question 18
Question
Which of the following will count down from 10 to 1 correctly?
Answer
-
for ( int j = 10; j <= 1; j++ )
-
for ( int j = 1; j <= 10; j++ )
-
for ( int j = 10; j > 1; j-- )
-
for ( int j = 10; j >= 1; j-- )
Question 19
Question
Which of the following does not contribute to improved software reusability?
Answer
-
Quickly creating new class libraries without testing them thoroughly.
-
Licensing schemes and protection mechanisms.
-
Descriptions of classes that allow programmers to determine whether a class fits their needs.
-
Cataloging schemes and browsing mechanisms.
Question 20
Question
What code may be filled in the blank without causing syntax or runtime errors:
public class Test {
java.util.Date date;
public static void main(String[ ] args) {
Test test = new Test();
System.out.println(________);
}
}
Answer
-
date
-
test.date
-
date.toString()
-
test.date.toString()
Question 21
Question
Which of the following is a valid identifier? (Choose all that apply.)
Question 22
Question
When should a program explicitly use the this reference?
Answer
-
Accessing a private variable.
-
Accessing a public variable.
-
Accessing a local variable.
-
Accessing a field that is shadowed by a local variable.
Question 23
Question
Variables that are shared by every instances of a class are ________.
Answer
-
class variables
-
public variables
-
private variables
-
instance variables
Question 24
Question
Which of the following is true? (Choose all that apply.)
Answer
-
The capacity of a string buffer can be automatically adjusted.
-
You can reverse the characters in a string buffer.
-
You can add characters into a string buffer.
-
You can delete characters into a string buffer.
Question 25
Question
Which of the following is arranged in increasing size order?
Answer
-
field, bit, file, record.
-
byte, file, database, record.
-
byte, field, file, record.
-
bit, field, record, file.
Question 26
Question
Which method can be used to read a whole line from the file?
Answer
-
nextInt
-
next
-
nextLine
-
nextDouble
Question 27
Question
-24 % -5 is ________.
Question 28
Question
Analyze the following code.
public class Test {
public static void main(String[ ] args) {
int month = 09;
System.out.println("month is " + month);
}
}
Answer
-
The program displays month is 9.0
-
The program displays month is 9
-
The program displays month is 09
-
The program has a syntax error, because 09 is an incorrect literal value.
Question 29
Question
A decision symbol in an activity diagram takes the shape of a ________.
Answer
-
Diamond.
-
Rectangle.
-
Circle.
-
Triangle.
Question 30
Question
Analyze the following code.
// Program 1:
public class Test {
public static void main(String[ ] args) {
Object a1 = new A();
Object a2 = new A();
System.out.println(a1.equals(a2));
}
}
class A {
int x;
public boolean equals(Object a) {
return this.x == ((A)a)x;
}
}
// Program 2:
public class Test {
public static void main(String[ ] args) {
Object a1 = new A();
Object a2 = new A();
System.out.println(a1.equals(a2));
}
}
class A {
int x;
public boolean equals(A a) {
return this.x == a.x;
}
}
Answer
-
Program 1 displays true and Program 2 displays true
-
Program 1 displays true and Program 2 displays false
-
Program 1 displays false and Program 2 displays true
-
Program 1 displays false and Program 2 displays false
Question 31
Question
Which correctly creates an array of five empty Strings?
Answer
-
String[ ] a = new String [5];
-
String[ ] a = new String [5]; for (int i = 0; i < 5; a[i++] = null);
-
String[ ] a = {"", "", "", "", ""};
-
String[5] a;
Question 32
Question
Which of the following are Java keywords?
Answer
-
instanceof
-
instanceOf
-
casting
-
cast
Question 33
Question
When you return an array from a method, the method returns ________.
Question 34
Question
What is the output of the following code?
public class Test {
public static void main(String[ ] args) {
String s1 = new String("Welcome to Java!");
String s2 = new String("Welcome to Java!");
if (s1 == s2)
System.out.println("s1 and s2 reference to the same String object");
else
System.out.println("s1 and s2 reference to different String objects");
}
}
Question 35
Question
Which of the following should usually be private?
Answer
-
Methods.
-
Constructors.
-
Variables (or fields).
-
All of the above.
Question 36
Question
When an argument is passed by reference:
Answer
-
a copy of the argument’s value is passed to the called method.
-
changes to the argument do not affect the original variable’s value in the caller.
-
the called method can access the argument’s value in the caller directly and modify that data.
-
the original value is removed from memory.
Question 37
Question
How many times will the following code print "Welcome to Java"?
int count = 0;
do {
System.out.println("Welcome to Java");
} while (count++ < 10);
Question 38
Question
Suppose TestCircle and Circle in Listing 7.1 in the textbook are in two separate files named TestCircle.java and Circle.java, respectively. What is the outcome of compiling TestCircle.java and then Circle.java?
Answer
-
Only TestCircle.java compiles.
-
Both compile fine.
-
Neither compiles successfully.
-
Only Circle.java compiles.
Question 39
Question
The default value for data field of a boolean type, numeric type, object type is ________, respectively.
Answer
-
true, 1, Null
-
true, 1, null
-
false, 0, null
-
false, 1, null
-
true, 0, null
Question 40
Question
Which of the following is not a valid Java identifier?
Answer
-
my Value
-
$_AAA1
-
width
-
m_x
Question 41
Question
Consider the array:
s[ 0 ] = 7
s[ 1 ] = 0
s[ 2 ] = -12
s[ 3 ] = 9
s[ 4 ] = 10
s[ 5 ] = 3
s[ 6 ] = 6
The value of s[ s[ 6 ] - s[ 5 ] ] is
Question 42
Question
Which of the following is not a superclass/subclass relationship?
Question 43
Question
Which of the following is the shape of an action-state symbol?
Question 44
Question
Analyze the following code:
public class Test1 {
public static void main(String[ ] args) {
xMethod(new double[ ]{3, 3});
xMethod(new double[5]);
xMethod(new double[3]{1, 2, 3});
}
public static void xMethod(double[ ] a) {
System.out.println(a.length);
}
}
Answer
-
The program has a compile error because xMethod(new double[ ]{3, 3}) is incorrect.
-
The program has a compile error because xMethod(new double[3]{1, 2, 3}) is incorrect.
-
The program has a compile error because xMethod(new double[5]) is incorrect.
-
The program has a runtime error because a is null.
Question 45
Question
What is output by the following Java code segment?
int temp;
temp = 180;
if ( temp > 90 )
{
System.out.println( "This porridge is too hot." );
// cool down
temp = temp – ( temp > 150 ? 100 : 20 );
} // end if
else
{
if ( temp < 70 )
{
System.out.println("This porridge is too cold.");
// warm up
temp = temp + (temp < 50 ? 30 : 20);
} // end if
} // end else
if ( temp == 80 )
System.out.println( "This porridge is just right!" );
Answer
-
This porridge is too hot.
-
This porridge is too cold. This porridge is just right!
-
This porridge is just right!
-
None of the above.
Question 46
Question
A method must declare to throw ________.
Answer
-
Error
-
unchecked exceptions
-
checked exceptions
-
RuntimeException
Question 47
Question
What is displayed on the console when running the following program?
class Test {
public static void main(String[ ] args) {
try {
System.out.println("Welcome to Java");
int i = 0;
int y = 2/i;
System.out.println("Welcome to Java");
}
catch (RuntimeException ex) {
System.out.println("Welcome to Java");
}
finally {
System.out.println("End of the block");
}
System.out.println("End of the block");
}
}
Answer
-
The program displays Welcome to Java three times followed by End of the block.
-
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.
-
You cannot catch RuntimeException errors.
Question 48
Question
Which syntax imports all static members of class Math?
Answer
-
static import java.lang.Math.*.
-
import static java.lang.Math.*.
-
static import java.lang.Math.
-
import static java.lang.Math.
Question 49
Question
The StringBuilder methods ________ not only change the contents of a string buffer, but also returns a reference to the string buffer. (Choose all that apply.)
Answer
-
delete
-
replace
-
append
-
reverse
-
insert
Question 50
Question
Every letter in a Java keyword is in lowercase.
Question 51
Question
Math.pow(2, 3) returns ________.
Question 52
Question
Which of the following classes cannot be extended?
Question 53
Question
In an expression containing values of the types int and double, the ________ values are ________ to ________ values for use in the expression.
Answer
-
int, promoted, double.
-
int, demoted, double.
-
double, promoted, int.
-
double, demoted, int.
Question 54
Question
Having a this reference allows:
Answer
-
a method to refer explicitly to the instance variables and other methods of the object on which the method was called.
-
a method to refer implicitly to the instance variables and other methods of the object on which the method was called.
-
an object to reference itself.
-
All of the above.
Question 55
Question
An instance of ________ describes programming errors, such as bad casting, accessing an out-of-bounds array, and numeric errors..
Answer
-
Exception
-
NumberFormatException
-
Error
-
RuntimeException
-
Throwable
Question 56
Question
Analyze the following code.
// Program 1
public class Test {
public static void main(String[ ] args) {
Object a1 = new A();
Object a2 = new A();
System.out.println(((A)a1).equals((A)a2));
}
}
class A {
int x;
public boolean equals(A a) {
return this.x == a.x;
}
}
// Program 2
public class Test {
public static void main(String[ ] args) {
A a1 = new A();
A a2 = new A();
System.out.println(a1.equals(a2));
}
}
class A {
int x;
public boolean equals(A a) {
return this.x == a.x;
}
}
Answer
-
Program 1 displays false and Program 2 displays false
-
Program 1 displays true and Program 2 displays true
-
Program 1 displays true and Program 2 displays false
-
Program 1 displays false and Program 2 displays true
Question 57
Question
How many significant digits does a double variable have?
Question 58
Question
In Java graphics, coordinate units are measured in ________.
Answer
-
dots.
-
pixels.
-
points.
-
inches.
Question 59
Question
Which code fragment would correctly identify the number of arguments passed via the command line to a Java application, excluding the name of the class that is being invoked?
Answer
-
int count = 0; while (args[count] != null) count ++;
-
int count = args.length;
-
int count = args.length - 1;
-
int count=0; while (!(args[count].equals(""))) count ++;
Question 60
Question
The ________ method returns a raised to the power of b.
Answer
-
Math.pow(a, b)
-
Math.pow(b, a)
-
Math.power(a, b)
-
Math.exponent(a, b)
Question 61
Question
Which of the following will not produce a compiler error?
Answer
-
Changing the value of a constant after it is declared.
-
Changing the value at a given index of an array after it is created.
-
Using a final variable before it is initialized.
-
All of the above will produce compiler errors.
Question 62
Question
The default equals implementation determines:
Answer
-
whether two references refer to the same object in memory.
-
whether two references have the same type.
-
whether two objects have the same instance variables.
-
whether two objects have the same instance variable values.
Question 63
Question
Analyze the following code:
public class Test {
public static void main(String[ ] args) {
B b = new B();
b.m(5);
System.out.println("i is " + b.i);
}
}
class A {
int i;
public void m(int i) {
this.i = i;
}
}
class B extends A {
public void m(String s) {
}
}
Answer
-
The program has a compilation error, because m is overridden with a different signature in B.
-
The method m is not overridden in B. B inherits the method m from A and defines an overloaded method m in B.
-
The program has a runtime error on b.i, because i is not accessible from b.
-
The program has a compilation error, because b.m(5) cannot be invoked since the method m(int) is hidden in B.
Question 64
Question
What is the output of the following program?
import java.util.Date;
public class Test {
public static void main(String[ ] args) {
Date date = new Date(1234567);
m1(date);
System.out.print(date.getTime() + " ");
m2(date);
System.out.println(date.getTime());
}
public static void m1(Date date) {
date = new Date(7654321);
}
public static void m2(Date date) {
date.setTime(7654321);
}
}
Answer
-
7654321 1234567
-
1234567 7654321
-
7654321 7654321
-
1234567 1234567
Question 65
Question
Given the following method
static void nPrint(String message, int n) {
while (n > 0) {
System.out.print(message);
n--;
}
}
What is the printout of the call nPrint('a', 4)?
Answer
-
aaaa
-
aaa
-
invalid call
-
aaaaa
Question 66
Question
Which of the following can be used in the expression after keyword case?
A. a constant integral expression.
B. a character constant.
C. a constant.
D. an enumeration constant.
Answer
-
A and B.
-
A and C.
-
B and C.
-
All.
Question 67
Question
In array items, which expression below accesses the value at row 3 and column 4?
Answer
-
items[ 3 ].[ 4 ].
-
items[ 3[ 4 ] ].
-
items[ 3 ][ 4 ].
-
items[ 3, 4 ].
Question 68
Question
Which of the following is the correct statement to return JAVA?
Question 69
Question
Which statement is false?
Answer
-
The actual data representation used within the class is of no concern to the class's clients.
-
Clients generally care about what the class does but not how the class does it.
-
Clients are usually involved in a class's implementation.
-
Hiding the implementation reduces the possibility that clients will become dependent on class-implementation details.
Question 70
Question
Which of the following is not an arithmetic operator?
Question 71
Question
Which of the following classes is not used for file input?
Answer
-
FileInputStream
-
FileReader
-
ObjectInputStream
-
Formatter
Question 72
Question
Consider the code segment below.
if ( gender == 1 )
{
if ( age >= 65 )
++seniorFemales;
} // end if
This segment is equivalent to which of the following?
Answer
-
if ( gender == 1 || age >= 65 )
++seniorFemales;
-
if ( gender == 1 && age >= 65 )
++seniorFemales;
-
if ( gender == 1 AND age >= 65 )
++seniorFemales;
-
if ( gender == 1 OR age >= 65 )
++seniorFemales;
Question 73
Question
A final field should also be declared ________ if it is initialized in its declaration.
Answer
-
private.
-
public.
-
protected.
-
static.
Question 74
Question
The ________ method displays an input dialog for reading a string. (Choose all that apply.)
Answer
-
String string = JOptionPane.showInputDialog(null, "Enter a string", "Input Demo", JOptionPane.QUESTION_MESSAGE);
-
String string = JOptionPane.showInputDialog(null, "Enter a string");
-
String string = JOptionPane.showInputDialog("Enter a string");
-
String string = JOptionPane.showInputDialog("Enter a string", "Input Demo", JOptionPane.QUESTION_MESSAGE);
-
String string = JOptionPane.showMessageDialog(null, "Enter a string", "Input Demo", JOptionPane.QUESTION_MESSAGE);
Question 75
Question
A default constructor has how many parameters?
Question 76
Question
The ________ method immediately terminates the program.
Answer
-
System.stop(0);
-
System.halt(0);
-
System.terminate(0);
-
System.exit(0);
-
System.quit(0);
Question 77
Question
Sentinel-controlled repetition is also known as:
Answer
-
Definite repetition.
-
Indefinite repetition.
-
Multiple repetition.
-
Double repetition.
Question 78
Question
Polymorphism means ________.
Answer
-
that a class can extend another class
-
that data fields should be declared private
-
that a class can contain another class
-
that a variable of supertype can refer to a subtype object
Question 79
Question
Which of the following is not a syntax error?
Answer
-
System.out.println( 'Hello world!' ):
-
System.out.println( "Hello . world!" );
-
System.out.println( "Hello world!" );
-
System.out.println( Hello world! );
Question 80
Question
What is k after the following block executes?
{
int k = 2;
nPrint("A message", k);
}
System.out.println(k);
Question 81
Question
The _________ of a class are also called the public services or the public interface that the class provides to its clients.
Question 82
Question
Analyze the following code: (Choose all that apply.)
public class Test {
public static void main(String[ ] args) {
Object a1 = new A();
Object a2 = new Object();
System.out.println(a1);
System.out.println(a2);
}
}
class A {
int x;
public String toString() {
return "A's x is " + x;
}
}
Answer
-
When executing System.out.println(a1), the toString() method in the Object class is invoked.
-
When executing System.out.println(a1), the toString() method in the A class is invoked.
-
When executing System.out.println(a2), the toString() method in the Object class is invoked.
-
The program cannot be compiled, because System.out.println(a1) is wrong and it should be replaced by System.out.println(a1.toString());
Question 83
Question
What do the following statements do?
double[] array;
array = new double[ 14 ];
Answer
-
Create a double array containing 13 elements.
-
Create a double array containing 14 elements.
-
Create a double array containing 15 elements.
-
Declare but do not create a double array.
Question 84
Question
When you invoke a method with a parameter, the value of the argument is passed to the parameter. This is referred to as ________.
Answer
-
pass by name
-
pass by value
-
pass by reference
-
method invocation
Question 85
Question
Which of following is not a correct method in Character? (Choose all that apply.)
Answer
-
isDigit()
-
toLowerCase(char)
-
isLetter(char)
-
toUpperCase()
-
isLetterOrDigit(char)
Question 86
Question
Given the following classes and their objects:
class C1 {};
class C2 extends C1 {};
class C3 extends C1 {};
C2 c2 = new C2();
C3 c3 = new C3();
Analyze the following statement:
c2 = (C2)((C1)c3);
Answer
-
You will get a runtime error because you cannot cast objects from sibling classes.
-
You will get a runtime error because the Java runtime system cannot perform multiple casting in nested form.
-
c3 is cast into c2 successfully.
-
The statement is correct.
Question 87
Question
Every class in Java, except ________, extends an existing class.
Answer
-
Integer.
-
Object.
-
String.
-
Class.
Question 88
Question
By default, the classpath consists only of the ________. However, the classpath can be modified by providing the ________ option to the javac compiler.
Answer
-
root directory of the package, -d.
-
current directory, -d.
-
root directory of the package, -classpath.
-
current directory, -classpath.
Question 89
Question
Which of the following is not a compilation error?
Answer
-
Neglecting to initialize a local variable in a method before it is used.
-
Placing a semicolon at the end of the first line of an if statement.
-
Omitting the left and right parenthesis for the condition of an if statement.
-
All are compilation errors.
Question 90
Question
________ is a simple but incomplete version of a method.
Question 91
Question
What is displayed by the following code?
public static void main(String[ ] args) throws Exception {
String[ ] tokens = "Welcome to Java".split("o");
for (int i = 0; i < tokens.length; i++) {
System.out.print(tokens[i] + " ");
}
}
Answer
-
Welcome t Java
-
Welc me t Java
-
Welc me to Java
-
Welcome to Java
Question 92
Question
Which of the following code segments does not increment val by 3:
Answer
-
val += 3;
-
val = val+1;
val = val+1;
val = val+1;
-
c = 3;
val = val + (c == 3 ? 2 : 3);
-
All of the above increment val by 3.
Question 93
Question
The import declaration import *; ________.
Answer
-
causes a compilation error.
-
imports all classes in the library.
-
imports the default classes in the library.
-
imports the classes in package java.lang.
Question 94
Question
An instance of ________ describes system errors. If this type of error occurs, there is little you can do beyond notifying the user and trying to terminate the program gracefully.
Answer
-
RuntimeException
-
Throwable
-
Error
-
Exception
-
NumberFormatException
Question 95
Question
An instance of ________ describes the errors caused by your program and external circumstances. These errors can be caught and handled by your program.
Answer
-
NumberFormatException
-
Error
-
RuntimeException
-
Throwable
-
Exception
Question 96
Question
What is the value of result after the following Java statements execute?
int a, b, c, d, result;
a = 4;
b = 12;
c = 37;
d = 51;
result = d % a * c + a % b + a;
Question 97
Question
When method printf requires multiple arguments, the arguments are separated with ________.
Answer
-
colons (:).
-
semicolons (;).
-
commas (,).
-
periods (.).
Question 98
Question
Analyze the following statement:
double sum = 0;
for (double d = 0; d<10;) {
d += 0.1;
sum += sum + d;
}
Answer
-
The program compiles and runs fine.
-
The program runs in an infinite loop because d<10 would always be true.
-
The program has a compile error because the control variable in the for loop cannot be of the double type.
-
The program has a compile error because the adjustment is missing in the for loop.
Question 99
Question
Suppose x is 1. What is x after x -= 1?
Question 100
Question
Stacks are known as ________ data structures.
Question 101
Question
Which statement is true when a superclass has protected instance variables?
Answer
-
A subclass object can assign an invalid value to the superclass’s instance variables, thus leaving an object in an inconsistent state.
-
Subclass methods are more likely to be written so that they depend on the superclass’s data implementation.
-
We may need to modify all the subclasses of the superclass if the superclass implementation changes.
-
All of the above.
Question 102
Question
If you enter 1 2 3, when you run this program, what will be the output?
import java.util.Scanner;
public class Test1 {
public static void main(String[ ] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter three numbers: ");
double number1 = input.nextDouble();
double number2 = input.nextDouble();
double number3 = input.nextDouble();
// Compute average
double average = (number1 + number2 + number3) / 3;
// Display result
System.out.println(average);
}
}
Question 103
Question
Suppose ArrayList x contains two strings [Beijing, Singapore]. Which of the following methods will cause the list to become [Beijing, Chicago, Singapore]?
Answer
-
x.add(2, "Chicago")
-
x.add(1, "Chicago")
-
x.add("Chicago")
-
x.add(0, "Chicago")
Question 104
Question
Which of the following statements are true?
Answer
-
If a file (e.g., c:\temp.txt) does not exist, new File("c:\\temp.txt") creates a new file named c:\temp.txt.
-
If a directory (e.g., c:\liang) does not exist, new File("c:\liang") creates a new directory named c:\liang.
-
If a directory (e.g., c:\liang) does not exist, new File("c:\liang") returns null.
-
If a file (e.g., c:\temp.txt) does not exist, new File("c:\\temp.txt") returns null.
-
None of the above.
Question 105
Question
The visibility of these modifiers increases in this order:
Answer
-
none (if no modifier is used), private, protected, and public.
-
none (if no modifier is used), protected, private, and public.
-
private, protected, none (if no modifier is used), and public.
-
private, none (if no modifier is used), protected, and public.