Threads

Question 1

What are the possible states of a thread in Java?

Answer 1

New, Runnable, Waiting, Timed Waiting, Blocked, Terminated

Question 2

What state does a thread enter when it is created but not yet started?

Answer 2

New

Question 3

What happens when a thread is in the Runnable state?

Answer 3

It is considered to be executing its task

Question 4

What is the Waiting state in a thread life cycle?

Answer 4

A state where a runnable thread waits for another thread to perform a task

Question 5

What is the Timed Waiting state?

Answer 5

A state where a runnable thread waits for a specified interval of time

Question 6

When does a thread return to the Runnable state from Timed Waiting?

Answer 6

When the time interval expires or when it is notified by another thread

Question 7

What causes a thread to enter the Blocked state?

Answer 7

When it attempts a task that cannot be completed immediately

Question 8

What is the Terminated state?

Answer 8

A state when a runnable thread successfully completes its task or terminates

Question 9

What does the JVM see when a thread is in the Runnable state?

Answer 9

It sees only the Runnable state, not the underlying Ready and Running states

Question 10

What is thread scheduling in an operating system?

Answer 10

The process that determines which thread runs next based on priorities

Question 11

What is a thread’s priority in Java?

Answer 11

A value that helps determine the order in which threads are scheduled

Question 12

True or False: Higher-priority threads are guaranteed to execute before lower-priority threads.

Answer 12

False

Question 13

What is timeslicing in the context of thread execution?

Answer 13

A method that allows threads of equal priority to share a processor

Question 14

What is the purpose of the Runnable interface?

Answer 14

To specify a task that can execute concurrently with other tasks

Question 15

What does the Executor interface do?

Answer 15

It manages a group of threads called a thread pool to execute Runnables

Question 16

What is the main advantage of using an Executor over creating threads manually?

Answer 16

It can reuse existing threads and optimize the number of threads for performance

Question 17

Define thread synchronization.

Answer 17

The coordination of access to shared data by multiple concurrent threads

Question 18

What is mutual exclusion in the context of thread synchronization?

Answer 18

Ensuring that only one thread accesses shared data at a time

Question 19

What type of data requires thread synchronization?

Answer 19

Shared mutable data

Question 20

What does marking a reference as final indicate?

Answer 20

The reference will not change, but it does not guarantee immutability of the object

Question 21

What are monitors in Java?

Answer 21

Built-in mechanisms for synchronization that ensure only one thread executes a block of code at a time

Question 22

What is the purpose of synchronized statements in Java?

Answer 22

To ensure that a thread must hold a monitor lock to execute a block of code

Question 23

What happens when a static method is declared synchronized?

Answer 23

The lock is on the class rather than on the instance of the object

Question 24

What is the problem with non-static synchronization?

Answer 24

Interference can occur between threads operating on different instances of the same class

Question 25

What does the synchronized keyword do?

Answer 25

It indicates that a method or block of code requires exclusive access