Ch8 Java

38 Questions | Total Attempts: 856

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Java Quizzes & Trivia

Questions and Answers
  • 1. 
    8.2 Q1: The _________ of a class are also called the public services or the public interface that the class provides to its clients.
    • A. 

      Public constructors.

    • B. 

      public instance variables.

    • C. 

      public methods

    • D. 

      All of the above.

  • 2. 
    The static method ________ of class String returns a formatted String.
    • A. 

      Printf

    • B. 

      Format

    • C. 

      FormatString

    • D. 

      ToFormatString

  • 3. 
    Which statement is false?
    • A. 

      The actual data representation used within the class is of no concern to the class’s clients

    • B. 

      Clients generally care about what the class does but not how the class does it

    • C. 

      Clients are usually involved in a class’s implementation

    • D. 

      Hiding the implementation reduces the possibility that clients will become dependent on class-implementation details

  • 4. 
    Which of the following should usually be private?
    • A. 

      Methods.

    • B. 

      Constructors

    • C. 

      Variables (or fields).

    • D. 

      All of the above.

  • 5. 
    Which of the following statements is true?
    • A. 

      Methods and instance variables can both be either public or private.

    • B. 

      Information hiding is achieved by restricting access to class members via keyword public.

    • C. 

      The private members of a class are directly accessible to the client of a class.

    • D. 

      None of the above is true.

  • 6. 
    When should a program explicitly use the this reference?
    • A. 

      Accessing a private variable

    • B. 

      Accessing a public variable

    • C. 

      Accessing a local variable.

    • D. 

      Accessing a field that is shadowed by a local variable

  • 7. 
    Having a this reference allows:
    • A. 

      A method to refer explicitly to the instance variables and other methods of the object on which the method was called.

    • B. 

      A method to refer implicitly to the instance variables and other methods of the object on which the method was called.

    • C. 

      An object to reference itself.

    • D. 

      All of the above.

  • 8. 
     A constructor cannot:
    • A. 

      Be overloaded.

    • B. 

      Initialize variables to their defaults.

    • C. 

      Specify return types or return values.

    • D. 

      Have the same name as the class.

  • 9. 
    8.5 Q2: Constructors:
    • A. 

      Initialize instance variables.

    • B. 

      When overloaded, can have identical argument lists.

    • C. 

      When overloaded, are selected by number, types and order of types of parameters.

    • D. 

      A and c.

  • 10. 
     A programmer-defined constructor that has no arguments is called a ________.
    • A. 

      Zero-argument constructor.

    • B. 

      No-argument constructor.

    • C. 

      Default constructor

    • D. 

      Main constructor.

  • 11. 
     What happens when this is used in a constructor’s body to call another constructor of the same class if that call is not the first statement in the constructor?
    • A. 

      A compilation error occurs.

    • B. 

      A runtime error occurs.

    • C. 

      A logic error occurs.

    • D. 

      Nothing happens. The program compiles and runs.

  • 12. 
    When implementing a method, use the class’s set and get methods to access the class’s ________ data.
    • A. 

      Public

    • B. 

      Private

    • C. 

      Protected

    • D. 

      All of the above

  • 13. 
    Which statement is false?
    • A. 

      The compiler always creates a default constructor for a class.

    • B. 

      If a class’s constructors all require arguments and a program attempts to call a no-argument constructor to initialize an object of the class, a compilation error occurs.

    • C. 

      A constructor can be called with no arguments only if the class does not have any constructors or if the class has a public no-argument constructor

    • D. 

      None.

  • 14. 
    Set methods are also commonly called ________ methods and get methods are also commonly called ________ methods.
    • A. 

      Query, mutator.

    • B. 

      Accessor, mutator.

    • C. 

      Mutator, accessor.

    • D. 

      Query, accessor.

  • 15. 
    Using public set methods provides data integrity if:
    • A. 

      The instance variables are public.

    • B. 

      The instance variables are private

    • C. 

      The methods perform validity checking

    • D. 

      Both b and c.

  • 16. 
     Composition is sometimes referred to as a(n) ________.
    • A. 

      Is-a relationship.

    • B. 

      Has-a relationship.

    • C. 

      Many-in-one relationship.

    • D. 

      One-to-many relationship

  • 17. 
    : enum types are implicitly ________ and enum constants are implicitly ________.
    • A. 

      Final, static.

    • B. 

      Static, static.

    • C. 

      Static, final.

    • D. 

      Final, final

  • 18. 
     Which statement is false?
    • A. 

      An enum declaration is a comma-separated list of enum constants and may optionally include other components of traditional classes, such as constructors, fields and methods

    • B. 

      Any attempt to create an object of an enum type with operator new results in a compilation error.

    • C. 

      An enum constructor cannot be overloaded

    • D. 

      An enum constructor can specify any number of parameters

  • 19. 
    Which method returns an array of the enum’s constants?
    • A. 

      Values

    • B. 

      GetValues

    • C. 

      Constants

    • D. 

      GetConstants

  • 20. 
    Which of the following is false?
    • A. 

      Method finalize does not take parameters and has return type void.

    • B. 

      Memory leaks using Java are rare because of automatic garbage collection

    • C. 

      Objects are marked for garbage collection by method finalize.

    • D. 

      The garbage collector reclaims unused memory

  • 21. 
    Static class variables:
    • A. 

      Are final.

    • B. 

      Are public

    • C. 

      Are private

    • D. 

      Are shared by all objects of a class

  • 22. 
    Which of the following is false?
    • A. 

      A static method must be used to access private static instance variables

    • B. 

      A static method has no this reference

    • C. 

      A static method can be accessed even when no objects of its class have been instantiated

    • D. 

      A static method can call instance methods directly

  • 23. 
     Which syntax imports all static members of class Math?
    • A. 

      Static import java.lang.Math.*.

    • B. 

      Import static java.lang.Math.*.

    • C. 

      static import java.lang.Math

    • D. 

      Import static java.lang.Math

  • 24. 
     Instance variables declared final do not or cannot:
    • A. 

      Cause syntax errors if used as a left-hand value.

    • B. 

      Be initialized

    • C. 

      Be modified

    • D. 

      None

  • 25. 
    A final field should also be declared ________ if it is initialized in its declaration.
    • A. 

      Private

    • B. 

      Public

    • C. 

      Protected

    • D. 

      Static