CS 1054 FINAL True/False QC

A Java compiler translates Java byte code into source code.

False

A String object cannot be created with a new operator.

False

A class can only implement one interface at a time.

False

A class must have a getter and setter method for each instance variable.

False

A constructor cannot be overloaded.

False

A getter method always returns an integer value.

False

An ellipses (...) is used to specify a method that accepts command-line arguments.

False

Characters in Java are represented using the ASCII character set.

False

Each value of a case can be a constant, variable, or expression.

False

If A is true and B is false, what is the value of the expression A && B?

False

If both operands to the remainder operator (%) are positive, a divisor of n will produce a result in the range 1 to n.

False

In Java, object reference variables do not have to be declared.

False

In a program, a class must always be referred to using its fully qualified name.

False

Java programs cannot be run on a web page.

False

Java was created by the Oracle Corporation, and is now managed by Sun Microsystems.

False

String is a Java primitive type

False

The Java keyword new is a method that can be called to create objects.

False

The compiler will issue an error if you violate a Java programming convention.

False

The element type of an array can be any type except boolean.

False

Using the Java API in a program is a rare occurrence

False

Within a class, methods must have unique names.

False

The body of a while loop may never execute.

False The condition is checked first, and if it's false right away, the body of the loop is never executed.

If an array can hold N values, the valid indexes for that array range from 0 to N

False 0 to N-1

A Polyline is a closed shape

False A Polygon is closed, but a Polyline is not.

A for-each loop can be used to fill the values in an array.

False A for-each loop provides access to the elements in the array, but not to the array itself

A variable-length parameter list is specified by inserting a colon (:) between the type and the parameter name.

False A variable-length parameter is specified using an ellipses (...) between the type and parameter name.

Only strings with alphabetic characters can be compared using the compareTo method

False Any Unicode characters can be compared, including punctuation and digits.

Encapsulation makes is difficult for hackers to access your data.

False Encapsulation is not about guarding against security breeches

A one-dimensional array has only one element type, but a multidimensional array can hold several types of elements.

False Every array has a single element type. The difference is in how the values are arranged

A binary search works best on an unsorted list of values

False For binary search to work at all, the list of values must already be sorted.

An array of values must be passed to the constructor of a Polygon or Polyline.

False For either, the constructor can take a variable number of double values directly, or the vertices can be added later.

You cannot use command-line arguments in IDEs like Eclipse and NetBeans.

False In IDEs, program arguments are specified using a menu option or a separate tab in the Run window.

A binary search only works if the number of elements to search is odd.

False In that case, the "middle" element will be the first of the two middle elements.

A method can only be an accessor or a mutator but not both.

False It can be both, such as a method that changes an instance value and then returns the new value.

A runtime error occurs when a printf field width is insufficient to display a value

False It grows to accommodate the larger value.

The assignment operator has higher precedence than the arithmetic operators

False It has the lowest precedence of all operators

The Java Development Kit (JDK) is an example of an integrated development environment (IDE).

False It is a "command-line" environment.

The control variable must be declared in the for loop header.

False It often is, but might also be declared previously.

The compareTo method returns one of three values: -1, 0, or 1.

False It returns a negative integer, positive integer, or 0 (not necessarily -1 or 1).

Calling the System.exit method is the best way to terminate a program.

False It's best to exit "#dq8cleanly,"#dq8 but System.exit can be convenient when no further processing is required

The body of a for loop is always executed at least once.

False Like a while loop, if the condition is false initially, the body is never executed

A Scanner object can be used to both read and write text files in Java.

False No, a Scanner object is only used for input.

The relational operators can be used to put String objects in alphabetical order

False Objects like < can't be applied to objects

A linear search examines every element in the array.

False Once the target element is found, there is no need to keep searching the array

A null string and an empty string are equal.

False One is a reference that doesn't point to any object, while the other is a valid string that contains no characters.

The expression in a switch statement can be an int or double value.

False Only int, character, or enumeration constatnt (no floating point)

The println method accepts a variable number of parameters.

False Only takes one

The arithmetic operators have a lower precedence than the relational operators

False Other way around

Our implementation of a prime sieve uses an array of integers and sets the values to 0 when they are found not to be prime.

False Our implementation uses an array of boolean values, whose index values are determined to be prime or not

Java represents a color using the CMYK color model

False RGB Color model

Using the this reference is mandatory with all instance data references inside a method.

False Sometimes it is necessary, but most often the this is helpful for making code more readable.

A String object is immutable, which means it is created using the new operator

False Strings are immutable, but that means they cannot be changed once created

Unlike other loops, the do-while loop is not considered a repetition statement.

False Sure it is. Java has four repetition statements: while, do-while, for, and for-each

Constructors cannot be overloaded.

False Sure they can, and often are. Overloaded constructors provide different ways to set up an object.

Text color is determined by the font applied to a Text object.

False Text color is specified using the setFill method of the Text class.

When creating a Text object, you specify the position on which you want the text centered

False The coordinates specify where the leading (left) edge of the text begins

If left unspecified, the font applied to a Text object is 12 point Lucinda Grande.

False The default font used depends on the operating system running the program

Arrays can hold primitive types, but not objects

False The element type of an array can be either a primitive type or an object reference

To change the algorithm for finding a minimum value into one that finds a maximum value, the condition of the for loop would change

False The for loop could stay the same -- the condition of the if statement would change to find the biggest element.

The constructor of the Person class is called constructPerson.

False The name of a constructor always matches the name of the class.

The classic format for a getter method is to use the word "access" in front of the variable name

False The name of a getter method starts with "get". A method that returns a variable width is called getWidth.

Getter methods always return a String

False The return type of each getter method must match the type of the value being retrieved.

If the x position of a line's end point is bound, so must the y position, and vice versa

False The x and y values of a point can be bound independently.

There are exactly six primitive data types in Java.

False There are 8

A Polygon or Polyline can have at most 10 vertices.

False There is no practical limit on the number of vertices in either.

If bound, the x and y position of a line's end point must be bound to the same property.

False They can be bound to different properties, or not at all.

An object must be created when its object reference variable is declared

False They can be separate activities

A printf format specifier of %.3f will print a floating-point value truncated to 3 decimal places.

False Value is rounded, not truncated

The less than operator (<) should not be used to compare floating-point values

False You can

To be sure have found all possible prime numbers up to a certain number N, you need to repeat the sieve algorithm all the way up to N.

False You only have to use the sieve algorithm up to the square root of N

The String class is part of the java.util package.

False java.lang

The classes of the java.util package are automatically imported into every Java program.

False java.lang is only one

The not operator (!) requires two operands.

False only has one operand

A String literal cannot span multiple lines in a Java program

True

A for-each loop can always be translated into an equivalent for loop.

True

A for-each loop can be used to compute the sum of all values in an array.

True

A for-each loop cannot be used to print the elements in an array backwards

True

A for-each loop cannot be used to set the values in an array.

True

A for-each loop cannot be used to store values in an array.

True

A method that accepts a variable-length argument list can be passed a previously declared array.

True

A two-dimensional array is really a one-dimensional array of one-dimensional arrays

True

A two-dimensional array is suitable for storing tabular data.

True

An ArrayList is a collection that can be processed using a for-each loop.

True

An encapsulated object keeps other objects from changing the values of its instance data.

True

Arguments passed to a variable-length argument list are accessed in the method using an array.

True

By convention, Java command-line options begin with a dash, such as -o or -b.

True

Classes should be designed to have well-defined and limited interactions with other classes.

True

Command-line arguments are commonly used to specify program options when a program is run.

True

Constants can be declared with public visibility without violating encapsulation.

True

Finding a minimum value requires that every element in the array be considered

True

If A and B are both true, what is the value of the expression A || B?

True

If an instantiation list is used to create an array, the new operator is not used.

True

If obj1 and obj2 point to the same object, then obj1 == obj2 is true.

True

If you try to access an element outside of the valid index range for an array, an exception will be thrown.

True

In Java, an array is an object.

True

In a JavaFX Polygon object, the last vertex point is automatically connected to the first.

True

It is possible to create an array with more than two dimensions.

True

Java is a general-purpose programming language.

True

Java is an object-oriented programming language.

True

Java performs automatic garbage collection.

True

Java was created by a development team led by James Gosling

True

Most professional software developers avoid the do-while loop.

True

Scaling a JavaFX Group object causes each element in the group to be scaled by the same amount.

True

Swapping two elements in an array requires three assignment statements

True

The == operator tests for reference equality.

True

The Greek mathematician Eratosthenes came up with the idea of using a sieve algorithm to find prime numbers.

True

The Java keyword this is an explicit reference to the object on which a method is invoked.

True

The JavaFX graphics framework is designed to replace older technologies such as Swing and AWT.

True

The functionality of a for loop can always be written as a while loop.

True

The instanceof operator determines if an object reference variable is currently pointing to an object of a particular type.

True

The main method accepts an array of String as a parameter.

True

The maximum indexes of a two-dimensional array with 6 rows and 10 columns are 5 and 9, respectively.

True

The methods in a Java interface are abstract.

True

The printf method accepts a variable number of parameters.

True

The printf method is an example from the Java API that uses a variable-length parameter list.

True

The result of a relational operator can be assigned to a boolean variable.

True

The this reference can be used to call one constructor from another.

True

The values passed to a Polygon constructor represent the vertices of the polygon.

True

Traversing an array or collection means accessing each element one at a time.

True

Value equality is when the contents of two objects are the same.

True

Variables declared within a method cease to exist when the method returns control to the caller.

True

You cannot use relational operators (such as < or >) on objects.

True

An output file should always be closed when you're done using it or data may be lost.

True Forgetting to close an output file is a common error.

If A is true and B is false, then the expression A || B is true.

True If either operand is true it is true

Java source code cannot be executed directly by a computer

True It must first be translated into an executable form.

File I/O operations may throw checked exceptions.

True Since they are checked, your code must either handle them explicitly or at least acknowledge they may occur.

The return type of a method is not part of the method signature.

True The return value of a method can be ignored, so it doesn't help identify the method declaration to use

The signatures of all methods within a class must be unique.

True The signatures of all methods within a class must be unique.

The println method in the Java API is overloaded

True There's many versions of println. Each one accepts a single data element to print.

The print and println methods can be used to write data to a PrintWriter object

True They work just as they do in the System.out object.

An alpha channel value of 1.0 represents a fully opaque color.

True This is the default.

A Java interface cannot be instantiated

True Unlike a class, you cannot create an object from an interface.

Objects created from the Color class are immutable.

True Values can't be changed

The Text class and the Font class are part of the same package.

True javafx.scene.text

A String method can be called through a string literal.

True

A break statement is used at the end of each case of a switch statement to keep processing from continuing into the next case

True

A constant is created using the final modifier

True

A constant should not be declared with public visibility

True

A constructor of a class has the same name as the class.

True

A for loop could always be written as an equivalent while loop.

True

A numeric literal is an explicit number used in a program.

True

A rectangle's corners can be rounded using calls to the setArcWidth and setArcHeight methods.

True

A static import let's you refer to a static method without using its class name

True

A switch statement can always be rewritten as a series of nested if statements.

True

A widening conversion converts a primitive value to a larger primitive type.

True

An entire package can be imported using one import statement

True

An import statement tells the compiler which class you're referring to in a program.

True

Arial is an example of a font family.

True

Constants make maintenance tasks easier.

True

Each Person object has its own identification number.

True

Either end point of a line segment can be designated as the "start point."

True

Elements of the Java API are organized into packages.

True

Following a null reference will cause an exception to be thrown.

True

Full documentation about the Java API can be found online.

True

If either or both operands to the division operator (/) are floating-point values, then the result will be a floating-point value.

True

In some cases, a sentinel value can be used to signal the end of input.

True

Switch statements can only test equality; they cannot make relational comparisons like greater than (>).

True

The 'int' and 'short' data types both represent integers

True

The Java Virtual Machine is software.

True

The Math class contains a constant that represents the value pi to several digits.

True

The Math.PI constant represents pi to 15 decimal places

True

The body of a do-while loop is always executed at least one time

True

The expression count++ can stand as a statement on its own.

True

The field width in a printf format specifier determines the total number of characters to be used to print the value.

True

The first parameter to the printf method is the format string

True

The format method of the String class accepts the same parameters as the printf method.

True

The human eye has three types of color receptors that correspond to wavelengths of red, green, and blue.

True

Two classes can have the same name if they are in different packages.

True

Using a while loop to check each input value for correctness is a form of input validation.

True

Whether text is displayed in bold or italic type is a function of the font object applied to the text

True

Numeric primitive values in Java are signed.

True + or -

The toString method is automatically called when an object is printed.

True And when an object is concatenated with a string

If A and B are both false, then the expression A && B is false.

True Both have to be false

A printf format specifier changes the value in the corresponding parameter

False

A type cast is used to change the data type of a variable.

False

If A is false, then the B operand in the expression A || B is not evaluated.

False

Java constants cannot be created for floating-point values.

False

The exclusive or operator (^) produces results that are opposite to the regular or operator (||).

False

The expression x^y raises the value x to the power y.

False

The methods of the Math class are called through the class name because they are abstract.

False

An import statement should be written inside a class but before any methods.

False Above the class

The increment section of the for loop header always adds 1 to the loop control variable.

False Although its called the increment section, you can update the control variable in any way you'd like.

The byte data type represents a true or false value.

False Boolean

Internally, an uppercase letter ('A') is treated the same as its lowercase version ('a').

False Case sensitivity

The 'float' and 'long' data types both represent floating-point values.

False Long represents a long integer

The parameters to the Rectangle constructor represent the upper left corner and lower right corner of the rectangle.

False The first two represent the upper left corner, but the last two represent the rectangle's width and length, respectively

The font applied to a Text object determines whether that text is underlined or not.

False The font applied to a Text object determines whether that text is underlined or not.