Understanding Java Threads

What are the states in the thread lifecycle?

• Running, Paused, Completed

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

• Initialized, Active, Suspended

• Idle, Executing, Finished

Explain the difference between user threads and daemon threads.

• User threads cannot be terminated while daemon threads can.

• User threads are application-managed and essential for execution, while daemon threads are background threads that support user threads and can be terminated when no user threads are running.

• User threads are always faster than daemon threads.

• Daemon threads are used for user input handling.

What is the purpose of the synchronized keyword in Java?

• To enable automatic garbage collection in Java.

• To provide thread-safe access to methods or blocks of code.

• To improve the performance of single-threaded applications.

• To allow multiple threads to execute simultaneously without restrictions.

How can you prevent thread interference in Java?

• Implement thread-local storage for all shared resources.

• Use synchronization mechanisms like synchronized methods, locks, or concurrent data structures.

• Use volatile variables to share data between threads.

• Avoid using any form of locking or synchronization.

What is a thread pool and why is it used?

• A thread pool is used to manage and reuse a fixed number of threads for executing tasks concurrently, improving performance and resource efficiency.

• A thread pool is used to create new threads for each task, increasing overhead.

• A thread pool is a single thread that executes tasks sequentially.

• A thread pool is a collection of processes that run independently of each other.

Describe the RUNNABLE state in the thread lifecycle.

• The RUNNABLE state means the thread is terminated and cannot be executed anymore.

• The RUNNABLE state refers to a thread that is sleeping and not ready to run.

• The RUNNABLE state indicates a thread that is currently blocked and waiting for resources.

• The RUNNABLE state represents a thread that is ready to run and can be executed by the CPU.

What is the role of the wait() method in thread communication?

• The wait() method allows a thread to wait until it is notified by another thread, facilitating communication and synchronization between threads.

• The wait() method is used to create new threads.

• The wait() method pauses the entire program execution.

• The wait() method terminates the thread immediately.

How does the notify() method work in Java?

• The notify() method creates a new thread for execution.

• The notify() method wakes up a single thread waiting on the object's monitor.

• The notify() method releases the object's monitor immediately.

• The notify() method pauses the current thread until notified.

What is thread safety and why is it important?

• Thread safety guarantees faster execution of code regardless of thread count.

• Thread safety is only relevant for single-threaded applications.

• Thread safety is a method to increase memory usage in applications.

• Thread safety is the property that ensures safe execution of code by multiple threads, preventing data corruption.

Explain the concept of deadlock in multithreading.

• Deadlock is a situation in multithreading where two or more threads are unable to proceed because each is waiting for the other to release a resource.

• Deadlock happens when threads are scheduled in a way that they all finish at the same time.

• Deadlock occurs when a thread completes its execution and releases all resources.

• Deadlock is a state where threads run indefinitely without any interaction.