Why is ReentrantLock needed?
Summary of the article
ReentrantLock provides several advantages over the traditional wait and notify methods. It is more efficient, more reliable, and more flexible. It also provides a more reliable way to implement thread waiting and wakeup.
Lock is an interface. It defines a set of methods that all locks should have. ReentrantLock is a concrete class that implements the Lock interface. It implements all the methods defined in Lock, plus much more.
A thread can take a lock only once. Synchronized blocks don’t offer any mechanism of a waiting queue and after the exit of one thread, any thread can take the lock. This could lead to starvation of resources for some other thread for a very long period of time.
To prevent data anomalies and conflicts, database systems use locking mechanisms to control the access and modification of data by different transactions.
ReentrantReadWriteLock can provide higher performance when the read operations are more than write operations by controlling the AbstractQueuedSynchronizer$state carefully. If not, the overhead of controlling is higher than ReentrantLock.
Java’s answer to the traditional mutex is the reentrant lock, which comes with additional bells and whistles. It is similar to the implicit monitor lock accessed when using synchronized methods or blocks. With the reentrant lock, you are free to lock and unlock it in different methods but not with different threads.
In computer science, the reentrant mutex (recursive mutex, recursive lock) is a particular type of mutual exclusion (mutex) device that may be locked multiple times by the same process/thread, without causing a deadlock.
A ReentrantLock is owned by the thread last successfully locking, but not yet unlocking it. A thread invoking lock will return, successfully acquiring the lock, when the lock is not owned by another thread. The method will return immediately if the current thread already owns the lock.
The Semaphore, by design, is blind to which thread calls acquire() and release() methods, all it cares about is permit becomes available. If we need reentrant mutual exclusion or a simple mutex then ReentrantLock is the best choice.
Locking systems provide security and control access authorization. Whether in administrative buildings, production plants, public institutions, hospitals, commercial or private buildings, now more than ever security is a top priority in society.
DisadvantagesContention: some threads/processes have to wait until a lock (or a whole set of locks) is released.Overhead: the use of locks adds overhead for each access to a resource, even when the chances for collision are very rare.
Questions and Answers:
1. What would be advantages of using a ReentrantLock?
ReentrantLock provides several advantages over the traditional wait and notify methods. It is more efficient, more reliable, and more flexible. It also provides a more reliable way to implement thread waiting and wakeup.
2. What is the difference between lock and ReentrantLock?
Lock is an interface. It defines a set of methods that all locks should have. ReentrantLock is a concrete class that implements the Lock interface. It implements all the methods defined in Lock, plus much more.
3. What are the advantages of using a lock instead of synchronization?
A thread can take a lock only once. Synchronized blocks don’t offer any mechanism of a waiting queue and after the exit of one thread, any thread can take the lock. This could lead to starvation of resources for some other thread for a very long period of time.
4. What is the advantage of locking in a database?
To prevent data anomalies and conflicts, database systems use locking mechanisms to control the access and modification of data by different transactions.
5. What is the difference between ReentrantLock and ReentrantReadWriteLock?
ReentrantReadWriteLock can provide higher performance when the read operations are more than write operations by controlling the AbstractQueuedSynchronizer$state carefully. If not, the overhead of controlling is higher than ReentrantLock.
6. What is the difference between mutex and reentrant lock?
Java’s answer to the traditional mutex is the reentrant lock, which comes with additional bells and whistles. It is similar to the implicit monitor lock accessed when using synchronized methods or blocks. With the reentrant lock, you are free to lock and unlock it in different methods but not with different threads.
7. Is Reentrantlock a mutex?
In computer science, the reentrant mutex (recursive mutex, recursive lock) is a particular type of mutual exclusion (mutex) device that may be locked multiple times by the same process/thread, without causing a deadlock.
8. What is reentrant lock?
A ReentrantLock is owned by the thread last successfully locking, but not yet unlocking it. A thread invoking lock will return, successfully acquiring the lock, when the lock is not owned by another thread. The method will return immediately if the current thread already owns the lock.
9. What is the difference between semaphore and ReentrantLock?
The Semaphore, by design, is blind to which thread calls acquire() and release() methods, all it cares about is permit becomes available. If we need reentrant mutual exclusion or a simple mutex then ReentrantLock is the best choice.
10. What is the purpose of locking?
Locking systems provide security and control access authorization. Whether in administrative buildings, production plants, public institutions, hospitals, commercial or private buildings, now more than ever security is a top priority in society.
11. What are the disadvantages of using locks in concurrency?
Contention: some threads/processes have to wait until a lock (or a whole set of locks) is released. Overhead: the use of locks adds overhead for each access to a resource, even when the chances for collision are very rare.
What would be advantages of using a ReentrantLock
ReentrantLock provides several advantages over the traditional wait and notify methods. It is more efficient, more reliable, and more flexible. It also provides a more reliable way to implement thread waiting and wakeup.
What is the difference between lock and ReentrantLock
Lock is an interface. It defines a set of methods that all locks should have. ReentrantLock is a concrete class that implements the Lock interface. It implements all the methods defined in Lock , plus much more.
What are the advantages of using a lock instead of synchronization
A thread can take a lock only once. Synchronized blocks don't offer any mechanism of a waiting queue and after the exit of one thread, any thread can take the lock. This could lead to starvation of resources for some other thread for a very long period of time.
What is the advantage of locking in database
To prevent data anomalies and conflicts, database systems use locking mechanisms to control the access and modification of data by different transactions.
What is the difference between ReentrantLock and ReentrantReadWriteLock
ReentrantReadWriteLock can provide higher performance when the read operations are more than write operations by controlling the AbstractQueuedSynchronizer$state carefully. If not, the overhead of controlling is higher than ReentrantLock .
What is the difference between mutex and reentrant lock
Java's answer to the traditional mutex is the reentrant lock, which comes with additional bells and whistles. It is similar to the implicit monitor lock accessed when using synchronized methods or blocks. With the reentrant lock, you are free to lock and unlock it in different methods but not with different threads.
Is Reentrantlock a mutex
In computer science, the reentrant mutex (recursive mutex, recursive lock) is a particular type of mutual exclusion (mutex) device that may be locked multiple times by the same process/thread, without causing a deadlock.
What is reentrant lock
A ReentrantLock is owned by the thread last successfully locking, but not yet unlocking it. A thread invoking lock will return, successfully acquiring the lock, when the lock is not owned by another thread. The method will return immediately if the current thread already owns the lock.
What is the difference between semaphore and ReentrantLock
The Semaphore, by design, is blind to which thread calls acquire() and release() methods, all it cares about is permit becomes available. If we need reentrant mutual exclusion or a simple mutex then ReentrantLock is the best choice.
What is the purpose of locking
Locking systems provide security and control access authorization. Whether in administrative buildings, production plants, public institutions, hospitals, commercial or private buildings, now more than ever security is a top priority in society.
What are the disadvantages of using locks in concurrency
DisadvantagesContention: some threads/processes have to wait until a lock (or a whole set of locks) is released.Overhead: the use of locks adds overhead for each access to a resource, even when the chances for collision are very rare.
When to use ReentrantLock in Java
The ReentrantLock class implements the Lock interface which is used to enhance the multithreading. It provides the capability to avoid the use of synchronization to maintain the database consistency so that the waiting time of the threads can be reduced.
What are the differences between a ReentrantLock and a synchronized block
In case of synchronized keyword, a thread can be blocked waiting for lock, for an indefinite period of time and there was no way to control that. ReentrantLock provides a method called lockInterruptibly(), which can be used to interrupt thread when it is waiting for lock.
What is the main disadvantage of mutex lock
The major drawback of a mutex lock is that it lets the thread spinlock if the lock is not available. While one thread has acquired the lock and is in its critical section, all other threads attempting to acquire the lock are in a loop where the thread periodically checks whether the lock is available.
What is the difference between synchronized block and ReentrantLock
ReentrantLock performs better than synchronized in high concurrency scenarios. If there is an inter-thread communication scenario, the Condition API of Reentrantlock is more convenient to use than notify/wait .
Can semaphore replace mutex
A Mutex is different than a semaphore as it is a locking mechanism while a semaphore is a signalling mechanism. A binary semaphore can be used as a Mutex but a Mutex can never be used as a semaphore.
Is reentrant lock a mutex
In computer science, the reentrant mutex (recursive mutex, recursive lock) is a particular type of mutual exclusion (mutex) device that may be locked multiple times by the same process/thread, without causing a deadlock.
What is the advantage of locking
Locking is a mechanism to ensure data integrity while allowing maximum concurrent access to data. It is used to implement concurrency control when multiple users access table to manipulate its data at the same time.
Do I need rear locking differential
In off-road-focused vehicles, a locking differential is certainly preferred. On the Racetrack: Most commercial drivers don't use their vehicles for drag racing or track tests, but those with locking differentials tend to accelerate faster than models with open differentials, at least on straightaways.
What are the three common problems in concurrency control
The three main concurrency control problems are triggered by lost updates, uncommitted data, and inconsistent retrievals.
What are the three main problems associated with concurrency control
Concurrency control is important because the simultaneous execution of transactions over a shared database can create several data integrity and consistency problems. The three main problems are lost updates, uncommitted data, and inconsistent retrievals.
What is the difference between ReentrantLock and StampedLock in Java
ReentrantLock is, as its name and javadocs say, reentrant. StampedLock is not. StampedLock is a low-level building block with some fragile behavior and complex interaction with the java memory model.
How does ReentrantLock work internally in Java
The tryLock() method of ReentrantLock class holds the lock only when any other thread does not hold it at the time of invocation. If the current thread already holds this lock, then the hold count is incremented by one, and the method returns true.
Why do you need to use synchronized methods or blocks
A synchronized block or method allows only one thread at a time to execute on a given object, which will solve the problem of data inconsistency.
Why is mutex better than semaphore
A mutex object allows multiple process threads to access a single shared resource but only one at a time. On the other hand, semaphore allows multiple process threads to access the finite instance of the resource until available. In mutex, the lock can be acquired and released by the same process at a time.