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Can a thread acquire multiple locks?
Reentrant means that locks are bound to the current thread. A thread can safely acquire the same lock multiple times without running into deadlocks (e.g. a synchronized method calls another synchronized method on the same object).
Which method release the object lock?
release() method It is used to release an acquired lock. If the lock is locked, this method will reset it to unlocked, and return. Also this method can be called from any thread. When this method is called, one out of the already waiting threads to acquire the lock is allowed to hold the lock.
What is difference between class locking and object locking?
1. When class level lock is applied on one method synchronized(SomeClass. class) and on other method object level lock is applied synchronized(this) then, both can execute at same time. only when class level lock is applied on both methods then there is no concurrent execution.
How does a lock object work in Java?
When a thread enters line 1, it attempts to acquire the lock object and if the lock is not held by another thread, the current thread gets exclusive ownership on the lock object. If the lock is currently held by another thread, then the current thread blocks and waits until the lock is released.
When do you need to synchronize an object in Java?
Every Java object has a single lock associated with it. If unrelated operations within the class are forced to share the same lock, then they have to wait for the lock and must be executed one at a time. In this case, define a different mutex for each unrelated operation that requires synchronization.
How to acquire a read lock in Java?
Let’s see rules for acquiring the ReadLock or WriteLock by a thread: Read Lock – if no thread acquired the write lock or requested for it then multiple threads can acquire the read lock Write Lock – if no threads are reading or writing then only one thread can acquire the write lock Let’s see how to make use of the ReadWriteLock:
Which is the best lock implementation in Java?
Lock Implementations 1 4.1. ReentrantLock. ReentrantLock class implements the Lock interface. 2 4.2. ReentrantReadWriteLock. ReentrantReadWriteLock class implements the ReadWriteLock interface. 3 4.3. StampedLock. StampedLock is introduced in Java 8.