CODEWITHSUNDEEP
javaconcurrency
Jjreina
Jjreina

Reputation: 2713

Concurrency: synchronized versus lock

What is the difference between synchronized and lock in Java?

Upvotes: 2

Views: 549

Answers (2)

eldjon
eldjon

Reputation: 2840

Both synchronized keyword and Lock objects are used to achieve synchronization in Java. Synchronized operates on monitor mechanisms that each Object in Java possess while lock is a simpler object which is a building block of the monitor. i believe basically the question is about the difference between a monitor and a lock.

A lock such as a semaphore, is a simple mechanism that can achieve synchronization by mutual exclusion only. If one thread acquired (lock.acquire()) a particular lock no other thread can acquire the same lock until the first thread releases it (lock.release()). A monitor on the other side operates not only on mutual exclusion but on condition variables as well. In a scenario where thread T1 enters the monitor of an object thread T2 intends to enter the same monitor, T2 will wait until T1 exits the monitor and in modern JVM T2 will actually enter the monitor right after T1 exits.

Upvotes: 1

brabster
brabster

Reputation: 43600

synchronized is a language keyword; Locks are objects.

When a method or block of code is marked synchronized, you are saying that some lock object (which could be specified in the syntax of synchronized) must be obtained by the method or block before it can be executed.

Upvotes: 2

Related Questions