Understanding Java Threads

What are the states in the Java Thread Lifecycle?

• INITIALIZED

• NEW, RUNNABLE, BLOCKED, WAITING, TIMED_WAITING, TERMINATED

• COMPLETED

• RUNNING

Explain the difference between user threads and daemon threads.

• User threads are managed by the user and can run independently, while daemon threads run in the background and are terminated when user threads complete.

• User threads are always terminated first.

• Daemon threads can run independently of user threads.

• User threads cannot be managed by the user.

What is thread synchronization and why is it important?

• Thread synchronization is a mechanism to control access to shared resources by multiple threads, preventing data inconsistency.

• Thread synchronization is a technique to allocate more memory to threads.

• Thread synchronization is a method to increase the speed of thread execution.

• Thread synchronization is used to create more threads for better performance.

How can you achieve thread synchronization in Java?

• Implement a busy-wait loop for synchronization

• Use global variables for sharing data

• Rely on the Java garbage collector for thread management

• Use synchronized methods or blocks, or utilize java.util.concurrent locks.

What is the purpose of the synchronized keyword in Java?

• To ensure that methods run faster in multi-threaded environments.

• To allow multiple threads to access the same method simultaneously.

• To prevent any form of code execution in a multi-threaded context.

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

Describe the concept of a monitor in thread synchronization.

• A monitor is a type of hardware used for displaying graphics.

• A monitor is a programming language used for thread management.

• A monitor is a synchronization mechanism that ensures mutual exclusion and coordination among threads accessing shared resources.

• A monitor is a database system for storing thread data.

What is the Runnable interface and how is it used?

• The Runnable interface is a class that cannot be instantiated directly.

• The Runnable interface is a data structure for storing thread information.

• The Runnable interface is used to create graphical user interfaces in Java.

• The Runnable interface is a functional interface in Java that represents a task to be executed by a thread.

How do you implement the Runnable interface in a Java class?

• Create a class that extends Thread and override the start() method.

• Create a class that implements Runnable, override the run() method, and start a Thread with an instance of the class.

• Implement the Runnable interface in a method instead of a class.

• Use a lambda expression without defining a class to run the thread.

What is the difference between extending Thread and implementing Runnable?

• Extending Thread allows for multiple inheritance; implementing Runnable restricts to single inheritance.

• Extending Thread restricts to single inheritance; implementing Runnable allows multiple inheritance.

• Extending Thread is more flexible than implementing Runnable.

• Implementing Runnable is slower than extending Thread due to overhead.

What are the potential issues with thread safety?

• Simplified code structure

• Potential issues with thread safety include race conditions, deadlocks, and data inconsistency.

• Memory leaks

• Increased performance