Pattern Design Concurrency Patterns

Question 1

What is the primary purpose of the Active Object pattern in concurrent programming?

Accepted Answer

To decouple method execution from method invocation for objects that reside in their own thread of control

Answer

To serialize all method calls into a single thread of execution

Answer

To create a pool of threads that execute tasks on demand

Answer

To synchronize access to shared resources using mutual exclusion locks

Question 2

Which concurrency pattern ensures that only one thread can execute a critical section at a time by combining mutual exclusion with condition synchronization?

Accepted Answer

Monitor Object

Answer

Observer Pattern

Answer

Half-Sync/Half-Async

Answer

Thread Pool

Question 3

The Thread Pool pattern is primarily used to:

Accepted Answer

Limit the number of concurrent threads and reuse them across multiple tasks

Answer

Create a new thread for every incoming request to maximize responsiveness

Answer

Ensure threads execute tasks in a strict priority order

Answer

Share mutable data between threads without requiring synchronization

Question 4

Which pattern uses a shared queue to pass work items between threads that produce data and threads that consume it?

Accepted Answer

Producer-Consumer

Answer

Singleton

Answer

Decorator

Answer

Command

Question 5

The Read-Write Lock pattern allows:

Accepted Answer

Multiple readers simultaneously but only one writer at a time, with writers excluding all readers

Answer

Only one thread to either read or write at any given time

Answer

Multiple writers simultaneously but only one reader at a time

Answer

Threads to read and write simultaneously without any restriction

Question 6

What is the primary benefit of the Scheduler concurrency pattern?

Accepted Answer

It controls the order in which threads access shared resources based on a defined policy

Answer

It creates new threads dynamically whenever the system load increases

Answer

It increases CPU utilization by running all available threads simultaneously

Answer

It prevents deadlocks by detecting and breaking circular resource dependencies

Question 7

In concurrent programming, what is a Future (also called a Promise)?

Accepted Answer

A placeholder object representing a result that will be available asynchronously

Answer

A mechanism used to cancel a running thread immediately

Answer

A lock that prevents multiple threads from accessing a shared resource

Answer

A thread that runs indefinitely in the background processing events