Concurrent APIs

Runnable and Callable interface both are used in the multithreading environment.Callable is available in java.util.concurrent.Callable package and Runnable in java.lang.Thread. Difference between Runnable and Callable interface in java Runnable was introduced in java 1.0 version While Callable is an extended version of Runnable and introduced in java 1.5 to address the limitation of Runnable. Runnable […]

Exchanger class is introduced with java 1.5 with other classes such ConcurrentHashMap, CountDownLatch, Semaphores. Exchanger class is used to exchange object between two threads. Exchanger simply waits until two separate threads calls exchange method, when it happens, it exchanges data supplied by threads.Two threads can pair and swap objects between them. Exchanger class may be useful […]

In this tutorial, we are going to see about Semaphore in java. Semaphore is a class in java.util.concurrent package introduced in JDK 5. Semaphore basically maintains a set of permits, so there are two methods which are mainly used for semaphore. acquire release acquire() method is used to get a permit and if no. of […]

In this post, we will see difference between CountDownLatch and CyclicBarrier in java. Lets first see similarities among them. Both wait for specific number of threads or tasks to finish. Lets see differences between CountDownLatch and CyclicBarrier. CountDownLatch vs CyclicBarrier Parameter CountDownLatch CyclicBarrier Reuse It can not be reused once count reaches 0 It can […]

In this post, we will see about CyclicBarrier in java. CyclicBarrier was introduced in Java 5 with other concurrency utils such as CountDownLatch, ConcurrentHashMap and BlockingQueue. CyclicBarrier is synchronized aid which allows set of threads to wait for each other at common barrier points.It is called cyclic because it can be reused once waiting threads […]

As per java docs, CountDownLatch is synchronisation aid that allows one or more threads to wait until set of operations being performed in other threads completes.

ConcurrentHashMap was introduced in Java 5 with other concurrency utils such as CountDownLatch, CyclicBarrier and BlockingQueue. ConcurrentHashMap in java is very similar to HashTable but it provides better concurrency level. You might know , you can synchonize HashMap using Collections.synchronizedMap(Map). So what is difference between ConcurrentHashMap and Collections.synchronizedMap(Map)In case of Collections.synchronizedMap(Map), it locks whole HashTable […]

In this tutorial, we will see ReentrantReadWriteLock Example. ReentrantReadWriteLock supports semantics of ReentrantLock and also ReadWriteLock. ReadWriteLock has two locks, one for read and one for write. Request for read lock from multiple threads can be acquired if there is no write request. If there is a write request, no other thread will be able to […]

In this post, we will see about Java ExecutorCompletionService example. ExecutorCompletionService class implements CompletionService. This class returns Future object in completion order. Why you may need to use ExecutorCompletionService: Let’s understand with the help of scenario: Let’s say you have 5 tasks, you submit it to the executors and you want to perform some operation as soon […]