Question 1

Which method do you call to make a thread ineligible to run on the CPU for a set number of milliseconds?

Accepted Answer

The method to make a thread ineligible to run on the CPU for a set number of milliseconds is sleep(). The other options do not directly deal with the timing of the thread's execution.

Question 2

Which of the following does not create an object that can run in a thread, assuming the following MyRunnable class declaration?
public class MyRunnable implements Runnable { ...}
i.Runnable runnable = new Runnable();
II.Runnable runnable = new MyRunnable();
III.MyRunnable runnable = new MyRunnable();

Accepted Answer

Option I creates an instance of the Runnable interface, which cannot be executed directly in a thread. Option II creates an instance of MyRunnable that can be executed in a thread. Option III creates an instance of MyRunnable that can also be executed in a thread. Therefore, only option I does not create an object that can run in a thread.

Question 3

Suppose run1 and run2 are objects of the class MyRunnable, which implements the Runnable interface.What is the result of the following calls?
run1.run();
run2.run();

Accepted Answer

The run() method directly executes the code within the current thread, without starting a new thread. Therefore, calling run() on both run1 and run2 will result in sequential execution, not as independent threads. To start threads running the code in MyRunnable class, we need to create Thread objects and pass the MyRunnable objects as parameters to their constructors, then call start() method on the Thread objects.

Question 4

Which exception must be caught or declared when calling the sleep method?

Accepted Answer

The sleep method can throw an InterruptedException when another thread interrupts the sleeping thread. Therefore, this exception must be caught or declared. The other options are not related to the sleep method.

Question 5

When a thread is interrupted, the most common response is to terminate the ____________ method.

Accepted Answer

When a thread is interrupted, the most common response is to terminate the run method. The other options are not necessarily terminated when a thread is interrupted. sleep and await methods can throw InterruptedException but it is up to the programmer to decide what to do with it. The thread method is just a constructor and not a method that can be interrupted.

Question 6

When a sleeping thread is interrupted, an InterruptedException is generated.Where do you catch that exception?

Accepted Answer

The InterruptedException is generated when a sleeping thread is interrupted while executing the run() method. Therefore, it should be caught in the run() method itself to properly handle the interruption.

Question 7

Which of the following class declarations could run in a thread?
i.public interface MyRunnable extends Runnable { ...}
II.public class MyRunnable extends Runnable { ...}
III.public class MyRunnable implements Runnable { ...}

Accepted Answer

III is correct because `Runnable` is an interface, and classes implement interfaces rather than extending them. Option I is also correct in a way since interfaces can extend other interfaces, but in the context of running in a thread, an interface itself cannot be run; a class that implements the interface is needed. Option II is incorrect because `Runnable` is an interface, and you cannot extend an interface with a class; you must implement it.

Question 8

Given a two-CPU machine and four threads, how many of the threads can execute in parallel?

Accepted Answer

With a two-CPU machine, two threads can execute in parallel simultaneously on each CPU, allowing for a total of four threads to execute concurrently.

Question 9

Which constructor can be used to create a new thread associated with a Runnable object?

Accepted Answer

Option A provides a constructor that takes a Runnable object as a parameter and creates a new thread associated with that object. Option B creates a new thread with no Runnable object associated with it. Option C provides a constructor that takes a Thread object as a parameter, which is not useful for creating a new thread associated with a Runnable object. Option D provides a constructor that takes a string as a parameter, which is used to specify the name of the thread but does not create a new thread associated with a Runnable object.

Question 10

For threads of equal priority, which is guaranteed by the thread scheduler that is part of the Java Virtual Machine?
i.All will get time on the CPU
II.All will get exactly equal time on the CPU
III.The order threads run in the CPU will always be the same

Accepted Answer

The thread scheduler of the JVM guarantees that all threads of equal priority will get time on the CPU. However, it does not guarantee that they will all get exactly equal time on the CPU, and it also does not guarantee that the order in which the threads run on the CPU will always be the same. Therefore, only statement I is correct.

Question 11

In which method are the tasks that are performed by a thread coded?

Accepted Answer

The tasks that are performed by a thread are coded in the run() method.

Question 12

When a sleeping thread is interrupted, a(n) ____________________ is generated.

Accepted Answer

When a sleeping thread is interrupted, it generates an InterruptedException. This exception is thrown by the JVM when a thread is waiting, sleeping or occupied with I/O operations, and it receives an interrupt signal. Therefore, the correct choice is D) InterruptedException.

Question 13

Each thread runs for a short amount of time, called a ____________________.

Accepted Answer

The term "time slice" refers to the short amount of time that each thread is given to run in a multitasking operating system. It is also known as a "quantum" or "time quantum". Therefore, option C is the best choice.

Question 14

The ________ method stops the current thread for a given number of milliseconds.

Accepted Answer

The sleep method is used to pause the execution of the current thread for a specified amount of time in milliseconds. The other options (run, await, delay) do not have the same functionality as sleep.

Question 15

To start a thread, you should first construct an object from a class that implements the ____________ interface.

Accepted Answer

The correct interface that needs to be implemented to start a thread is the Runnable interface. A class that implements the Runnable interface can be used as an argument to create a new Thread object, which will execute the run() method of the Runnable object. Therefore, the best choice is D, which is Runnable.

Question 16

The Runnable interface includes which method(s)?
i.public void run(Runnable runnable)
II.public void run()
III.public void start()

Accepted Answer

The Runnable interface includes only one method - public void run(). The other two methods mentioned (public void run(Runnable runnable) and public void start()) are not part of the Runnable interface.

Question 17

The _____________ interface is designed to encapsulate the concept of a sequence of statements that can run in parallel with other tasks, without equating it with the concept of a thread, a potentially expensive resource that is managed by the operating system.

Accepted Answer

The Runnable interface is designed for defining a sequence of statements that can run in parallel with other tasks, without equating it with the concept of a thread. It is a lightweight interface that can be used as an alternative to creating a Thread, which can be expensive and resource-intensive. Therefore, option B is the best choice.

Question 18

If you do not use the Runnable interface, what is necessary to create a new thread?
i.Implement the Threadable interface
II.Extend the Thread class and add a run() method to it
III.Add a run method to any class

Accepted Answer

To create a new thread without using the Runnable interface, you must extend the Thread class and override its run() method. The Threadable interface does not exist in Java. Adding a run method to any class without extending Thread or implementing Runnable does not suffice for creating a thread.

Question 19

Which method(s) are part of the Thread class?
i.public void run(Runnable runnable)
II.public void start(Runnable runnable)
III.public void start()

Accepted Answer

The correct method that is part of the Thread class is "public void start()". The start() method is used to begin the execution of the thread. The run() method exists but does not take a Runnable as a parameter; instead, it has no parameters. There is no start(Runnable runnable) method in the Thread class.

Question 20

Insert the statement that would start the following thread.
Thread firstThread = new Thread(myRunnable);
____________________

Accepted Answer

To start a new thread with a Runnable object, we need to create a new Thread with that Runnable object and then call its start() method. This will execute the run() method of the Runnable in a new thread. Therefore, we need to choose the option B which calls the start() method on the firstThread object.

Quiz 22: Multithreading

Which method do you call to make a thread ineligible to run on the CPU for a set number of milliseconds?

Suppose run1 and run2 are objects of the class MyRunnable, which implements the Runnable interface.What is the result of the following calls? run1.run() ; run2.run() ;

Which exception must be caught or declared when calling the sleep method?

When a thread is interrupted, the most common response is to terminate the ____________ method.

When a sleeping thread is interrupted, an InterruptedException is generated.Where do you catch that exception?

Which of the following class declarations could run in a thread? i.public interface MyRunnable extends Runnable { ...} II.public class MyRunnable extends Runnable { ...} III.public class MyRunnable implements Runnable { ...}

Given a two-CPU machine and four threads, how many of the threads can execute in parallel?

Which constructor can be used to create a new thread associated with a Runnable object?

For threads of equal priority, which is guaranteed by the thread scheduler that is part of the Java Virtual Machine? i.All will get time on the CPU II.All will get exactly equal time on the CPU III.The order threads run in the CPU will always be the same

In which method are the tasks that are performed by a thread coded?

When a sleeping thread is interrupted, a(n) ____________________ is generated.

Each thread runs for a short amount of time, called a ____________________.

The ________ method stops the current thread for a given number of milliseconds.

To start a thread, you should first construct an object from a class that implements the ____________ interface.

The Runnable interface includes which method(s) ? i.public void run(Runnable runnable) II.public void run() III.public void start()

The _____________ interface is designed to encapsulate the concept of a sequence of statements that can run in parallel with other tasks, without equating it with the concept of a thread, a potentially expensive resource that is managed by the operating system.

If you do not use the Runnable interface, what is necessary to create a new thread? i.Implement the Threadable interface II.Extend the Thread class and add a run() method to it III.Add a run method to any class

Which method(s) are part of the Thread class? i.public void run(Runnable runnable) II.public void start(Runnable runnable) III.public void start()

Insert the statement that would start the following thread. Thread firstThread = new Thread(myRunnable) ; ____________________