Threads

Question 1

Which Thread method enables a thread to wait on another thread before continuing its work?

Answer 1

join

Question 2

Which Thread method executes the run method on a child thread?

Answer 2

start

Question 3

Which term describes how responsive an application is during execution?

Answer 3

Liveness

Question 4

Liveness

Answer 4

A concurrent application’s ability to execute in a timely manner is known as its liveness.

Question 5

What types of problems can effect an applications liveness?

Answer 5

deadlock, starvation, livelock

Question 6

Which term occurs when one or more threads access a shared resource so frequently that other threads are unable to gain needed access?

Answer 6

starvation

Question 7

Which term describes controlled thread access to a shared resource, so as to reduce the likelihood of memory consistency errors between threads?

Answer 7

Synchronization

Question 8

What is the effect of invoking the start method more than once on the same thread?

Answer 8

An IllegalThreadStateException is thrown.

Question 9

Which term describes actions that are indivisible and cannot be stopped prematurely before they complete?

Answer 9

Atomicity

Question 10

Which Thread attribute is used to control the relative likelihood and frequency that a thread will be given a time slice to execute?

Answer 10

priority

Question 11

What is the Thread priority range?

Answer 11

1-10

Question 12

Which term occurs when two or more threads are blocked forever while waiting for access to the same resource and are unable to complete their tasks?

Answer 12

Deadlock

Question 13

Which keyword declares a method, block, or code that is limited to a single concurrent thread?

Answer 13

synchronized

Question 14

Which term occurs when two or more threads are too busy responding to each other to complete their tasks?

Answer 14

livelock

Question 15

Which Thread attribute is used to control whether the JVM may exit before the thread terminates?

Answer 15

daemon

Question 16

What does the Thread.yield() method do

Answer 16

It provides a hint to the scheduler that the current thread is willing to yield its current use of a processor. The scheduler is free to ignore this hint.

Question 17

Given:
Executor ex = Executors.newScheduledThreadPool(5);
How many threads will be created when passing tasks to the Executor object?

Answer 17

Five threads will be created; each thread supporting a single task.

Question 18

Explain the Executors method:

newSingleThreadExecutor

Answer 18

Creates an Executor that uses a single worker thread operating off an unbounded queue. The returned executor is guaranteed not to be reconfigurable to use additional threads.

Question 19

Explain the Executors method:

newCachedThreadPool

Answer 19

Creates a thread pool that creates new threads as needed, but will reuse previously constructed threads when they are available.

Question 20

Explain the Executors method:

newFixedThreadPool

Answer 20

Creates a thread pool that reuses a fixed number of threads operating off a shared unbounded queue. Number of fixed threads must be specified.

Question 21

Explain the Executors method:

newScheduledThreadPool

Answer 21

Creates a thread pool that can schedule commands to run after a given delay, or to execute periodically. Mujst specify the number of threads to keep in the pool even if they are idle.

Question 22

what does getRawResult return for a RecursiveAction object.

Answer 22

null