Question 1

Task is a _______ class.

Accepted Answer

A)  anonymous inner 
B)  composite 
C)  nested 
D)  generic 
A)  anonymous inner 
B)  composite 
C)  nested 
D)  generic D

Question 2

In a producer/consumer relationship, when a consumer finds the buffer empty or finds that the previous data has already been read, the consumer should call __________.

Accepted Answer

A)  lock 
B)  signal 
C)  sleep 
D)  await. 
A)  lock 
B)  signal 
C)  sleep 
D)  await. B

Question 3

Which of the following statements is false?

Accepted Answer

A)  Thread synchronization is necessary only for shared mutable data, i.e., data that may change during its lifetime. 
B)  With shared immutable data that will not change, it's not possible for a thread to see old or incorrect values as a result of another thread's manipulation of that data. 
C)  When you share immutable data across threads, declare the corresponding data fields XE "Keywords: final" XE "final:keyword" final to indicate that the values of the variables will not change after they're initialized. This prevents accidental modification of the shared data, which could compromise thread safety. 
D)  Labeling object references as final indicates that the referenced object is immutable. 
A)  Thread synchronization is necessary only for shared mutable data, i.e., data that may change during its lifetime. 
B)  With shared immutable data that will not change, it's not possible for a thread to see old or incorrect values as a result of another thread's manipulation of that data. 
C)  When you share immutable data across threads, declare the corresponding data fields XE "Keywords: final" XE "final:keyword" final to indicate that the values of the variables will not change after they're initialized. This prevents accidental modification of the shared data, which could compromise thread safety. 
D)  Labeling object references as final indicates that the referenced object is immutable. D

Question 4

Which of the following statements is false?

Accepted Answer

A)  Java makes concurrency available to you through the language and APIs. 
B)  Concurrency is a subset of parallelism. 
C)  Today's multi-core computers have multiple processors that can perform tasks in parallel. 
D)  Java programs can have multiple threads of execution, where each thread has its own method-call stack and program counter, allowing it to execute concurrently with other threads. This capability is called multithreading. 
A)  Java makes concurrency available to you through the language and APIs. 
B)  Concurrency is a subset of parallelism. 
C)  Today's multi-core computers have multiple processors that can perform tasks in parallel. 
D)  Java programs can have multiple threads of execution, where each thread has its own method-call stack and program counter, allowing it to execute concurrently with other threads. This capability is called multithreading.

Question 5

Which of the following is not true of ExecutorService?

Accepted Answer

A)  It is a subinterface of Executor. 
B)  It is an object that can be run in a separate thread. 
C)  It declares method shutdown. 
D)  It manages a group of threads. 
A)  It is a subinterface of Executor. 
B)  It is an object that can be run in a separate thread. 
C)  It declares method shutdown. 
D)  It manages a group of threads.

Question 6

To determine the difference between two Instants, use class Duration's static method ________, which returns a Duration object containing the time difference.

Accepted Answer

A)  difference 
B)  interval 
C)  between 
D)  span 
A)  difference 
B)  interval 
C)  between 
D)  span

Question 7

Which of the following statements is false?

Accepted Answer

A)  Task method updateProgress updates a Task's progress property, which represents the percentage completion. 
B)  Task method updateValue updates a Task's value property, which holds each intermediate value. 
C)  Task method isCancelled returns a boolean value indicating whether the Task has been cancelled. 
D)  All of the above are true. 
A)  Task method updateProgress updates a Task's progress property, which represents the percentage completion. 
B)  Task method updateValue updates a Task's value property, which holds each intermediate value. 
C)  Task method isCancelled returns a boolean value indicating whether the Task has been cancelled. 
D)  All of the above are true.

Question 8

Which one of the following statements is true with regard to a producer/consumer relationship with one producer and one consumer?

Accepted Answer

A)  A producer can never produce faster than the consumer is consuming. 
B)  A consumer can never consume faster than the producer is producing. 
C)  A producer can produce more items than a consumer consumes. 
D)  A consumer can consume more items than a producer produces. 
A)  A producer can never produce faster than the consumer is consuming. 
B)  A consumer can never consume faster than the producer is producing. 
C)  A producer can produce more items than a consumer consumes. 
D)  A consumer can consume more items than a producer produces.

Question 9

If a thread calls __________, then every thread waiting for the object becomes eligible to acquire the lock.

Accepted Answer

A)  signalEach 
B)  signalAll 
C)  signal 
D)  signalMethods 
A)  signalEach 
B)  signalAll 
C)  signal 
D)  signalMethods

Question 10

Which of the following is true for a correct producer/consumer relationship with one producer, one consumer, and a 5-cell buffer?

Accepted Answer

A)  The producer can produce when all cells are full. 
B)  The consumer can consume when all cells are full. 
C)  The consumer can consume when all cells are empty. 
D)  None of the above. 
A)  The producer can produce when all cells are full. 
B)  The consumer can consume when all cells are full. 
C)  The consumer can consume when all cells are empty. 
D)  None of the above.

Question 11

Duration method ________ returns the Duration as a long value in milliseconds.

Accepted Answer

A)  milliseconds 
B)  term 
C)  extent 
D)  toMillis 
A)  milliseconds 
B)  term 
C)  extent 
D)  toMillis

Question 12

NumberFormat method ________ returns a String representation of its argument in the specified numeric format.

Accepted Answer

A)  number 
B)  toNumeric 
C)  format 
D)  numeric 
A)  number 
B)  toNumeric 
C)  format 
D)  numeric

Question 13

Which of the following statements is false?

Accepted Answer

A)  A runnable thread can enter the XE "timed waiting state" timed waiting state for a specified interval of time. It transitions back to the runnable state when that time interval expires or when the event it's waiting for occurs. 
B)  Timed waiting threads and waiting threads can use a processor, if one is available. 
C)  A runnable thread can transition to the timed waiting state if it provides an optional wait interval when it's waiting for another thread to perform a task. Such a thread returns to the runnable state when it's notified by another thread or when the timed interval expires-whichever comes first. 
D)  Another way to place a thread in the timed waiting state is to put a runnable thread to sleep-a sleeping thread remains in the timed waiting state for a designated period of time (called a sleep interval), after which it returns to the runnable state. 
A)  A runnable thread can enter the XE "timed waiting state" timed waiting state for a specified interval of time. It transitions back to the runnable state when that time interval expires or when the event it's waiting for occurs. 
B)  Timed waiting threads and waiting threads can use a processor, if one is available. 
C)  A runnable thread can transition to the timed waiting state if it provides an optional wait interval when it's waiting for another thread to perform a task. Such a thread returns to the runnable state when it's notified by another thread or when the timed interval expires-whichever comes first. 
D)  Another way to place a thread in the timed waiting state is to put a runnable thread to sleep-a sleeping thread remains in the timed waiting state for a designated period of time (called a sleep interval), after which it returns to the runnable state.

Question 14

Which of the following statements is false?

Accepted Answer

A)  If an operation requires the executing thread to XE "lock:hold" XE "hold a lock" hold a lock while the operation is performed, a thread must XE "lock:acquire" XE "acquire a lock" relase the lock before proceeding with the operation. Other threads attempting to perform an operation that requires the same lock will be blocked until the first thread XE "lock:release" XE "release a lock" releases the lock, at which point the blocked threads may attempt to acquire the lock and proceed with the operation. 
B)  To specify that a thread must hold a monitor lock to execute a block of code, the code should be placed in a synchronized statement. 
C)  Code in a synchronized statement is said to be guarded by the monitor lock; a thread must acquire the lock to execute the guarded statements. 
D)  The monitor allows only one thread at a time to execute statements within synchronized statements that lock on the same object, as only one thread at a time can hold the monitor lock. The synchronized statements are declared using the synchronized keyword. 
A)  If an operation requires the executing thread to XE "lock:hold" XE "hold a lock" hold a lock while the operation is performed, a thread must XE "lock:acquire" XE "acquire a lock" relase the lock before proceeding with the operation. Other threads attempting to perform an operation that requires the same lock will be blocked until the first thread XE "lock:release" XE "release a lock" releases the lock, at which point the blocked threads may attempt to acquire the lock and proceed with the operation. 
B)  To specify that a thread must hold a monitor lock to execute a block of code, the code should be placed in a synchronized statement. 
C)  Code in a synchronized statement is said to be guarded by the monitor lock; a thread must acquire the lock to execute the guarded statements. 
D)  The monitor allows only one thread at a time to execute statements within synchronized statements that lock on the same object, as only one thread at a time can hold the monitor lock. The synchronized statements are declared using the synchronized keyword.

Question 15

An ExecutorService object is created by calling a static method of which class?

Accepted Answer

A)  Executor. 
B)  Executors. 
C)  ExecutorService. 
D)  Thread. 
A)  Executor. 
B)  Executors. 
C)  ExecutorService. 
D)  Thread.

Question 16

The Callable interface (of package java.util.concurrent) declares a single method named call that allows a task to return a value.

Accepted Answer

A)  call 
B)  execute 
C)  invoke 
D)  None of the above. 
A)  call 
B)  execute 
C)  invoke 
D)  None of the above.

Question 17

Arrays static method ________ applies a BinaryOperator to the current and previous array elements and stores the result in the current element.

Accepted Answer

A)  prefix 
B)  parallelSet 
C)  parallelApply 
D)  parallelPrefix 
A)  prefix 
B)  parallelSet 
C)  parallelApply 
D)  parallelPrefix

Question 18

The________ handles interactions with the application's controls, such as rendering controls or processing user actions like mouse clicks.

Accepted Answer

A)  JavaFX event-handling 
B)  JavaFX application 
C)  JavaFX GUI-handling 
D)  None of the above. 
A)  JavaFX event-handling 
B)  JavaFX application 
C)  JavaFX GUI-handling 
D)  None of the above.

Question 19

With timeslicing, each thread is given a limited amount of time, called a __________, to execute on a processor.

Accepted Answer

A)  quantum 
B)  burst 
C)  time allocation 
D)  scheduling interval 
A)  quantum 
B)  burst 
C)  time allocation 
D)  scheduling interval

Question 20

Which of the following statements is false?

Accepted Answer

A)  In a multithreaded application, threads can be distributed across multiple processors (if available) so that multiple tasks execute in parallel and the application can operate more efficiently. 
B)  The JVM creates threads to run a program and for housekeeping tasks such as garbage collection. 
C)  Multithreading can increase performance only on multi-core systems. 
D)  The vast majority of programmers should use existing collection classes and interfaces from the concurrency APIs that manage synchronization for you. 
A)  In a multithreaded application, threads can be distributed across multiple processors (if available) so that multiple tasks execute in parallel and the application can operate more efficiently. 
B)  The JVM creates threads to run a program and for housekeeping tasks such as garbage collection. 
C)  Multithreading can increase performance only on multi-core systems. 
D)  The vast majority of programmers should use existing collection classes and interfaces from the concurrency APIs that manage synchronization for you.

Exam 22: Concurrency

Task is a _______ class.

In a producer/consumer relationship, when a consumer finds the buffer empty or finds that the previous data has already been read, the consumer should call __________.

Which of the following statements is false?

Which of the following statements is false?

Which of the following is not true of ExecutorService?

To determine the difference between two Instants, use class Duration's static method ________, which returns a Duration object containing the time difference.

Which of the following statements is false?

Which one of the following statements is true with regard to a producer/consumer relationship with one producer and one consumer?

If a thread calls __________, then every thread waiting for the object becomes eligible to acquire the lock.

Which of the following is true for a correct producer/consumer relationship with one producer, one consumer, and a 5-cell buffer?

Duration method ________ returns the Duration as a long value in milliseconds.

NumberFormat method ________ returns a String representation of its argument in the specified numeric format.

Which of the following statements is false?

Which of the following statements is false?

An ExecutorService object is created by calling a static method of which class?

The Callable interface (of package java.util.concurrent) declares a single method named call that allows a task to return a value.

Arrays static method ________ applies a BinaryOperator to the current and previous array elements and stores the result in the current element.

The________ handles interactions with the application's controls, such as rendering controls or processing user actions like mouse clicks.

With timeslicing, each thread is given a limited amount of time, called a __________, to execute on a processor.

Which of the following statements is false?

Introduction to Computers, the Internet and Java

Introduction to Java Applications; Inputoutput and Operators

Introduction to Classes, Objects, Methods and Strings

Control Statements: Assignment, and Operators

Control Statements: Logical Operators

Methods: a Deeper Look

Arrays and Arraylists

Classes and Objects: a Deeper Look

Object-Oriented Programming: Inheritance

Object-Oriented Programming: Polymorphism and Interfaces

Exception Handling: a Deeper Look

Javafx Graphical User Interfaces

Javafx Gui

Strings, Characters and Regular Expressions

Files, Inputoutput Streams, Nio and Xml Serialization

Generic Collections

Lambdas and Streams

Recursion

Searching, Sorting and Big O

Generic Classes and Methods: a Deeper Look

Custom Generic Data Structures

Accessing Databases With Jdbc

Swing Gui Components

Graphics and Java 2d

Networking

Java Persistence Api Jpa

Javaserver Faces Web Apps

Javaserver Faces Web Apps

Swing Gui Components

Filters