threadpoolexecutor

This question already has an answer here: What is the difference between corePoolSize and maxPoolSize in the Spring ThreadPoolTaskExecutor 5 answers When a new task is submitted in method execute(java.lang.Runnable) ,and fewer than corePoolSize threads are running, a new thread is created to handle the request, even if other worker threads are idle. 1) Why there is a need to create a new thread to handle the request if there are idle threads? If there are more than corePoolSize but less than maximumPoolSize threads running, a new thread will be created only if the queue is full. 2) I don't

I am working on a multithreaded project in which I need to spawn multiple threads to measure the end to end performance of my client code, as I'm doing Load and Performance testing. So I created the below code which is using ExecutorService . Below is the code with ExecutorService : public class MultithreadingExample { public static void main(String[] args) throws InterruptedException { ExecutorService executor = Executors.newFixedThreadPool(20); for (int i = 0; i < 100; i++) { executor.submit(new NewTask()); } executor.shutdown(); executor.awaitTermination(Long.MAX_VALUE, TimeUnit.DAYS); } }

I have thread pool, which will take Callable worker thread with a RejectionHandler . I need to get this Callable task in RejectionHandler but unable to get it. In this below example, I need uniqueId of Callable task for which RejectionHandler executed. In RejecitonHandler , the Runnable is casted FutureTask where I expect that it should be casted to Callable worker thread. Please help me in getting Callable Worker thread instance in RejectionHandler . import java.util.Random; import java.util.concurrent.ArrayBlockingQueue; import java.util.concurrent.Callable; import java.util.concurrent

I've searched a lot but couldn't find any solution. I use java thread pool in such way: ExecutorService c = Executors.newFixedThreadPool(3); for (int i = 0; i < 10; ++i) { c.execute(new MyTask(i)); } In such way Tasks are executed in consequent order (as in queue). But I need change "select next task" strategy. So I want assign to each task specify priority (it isn't thread priority) and execute tasks correspond to these priorities. So when executor have finished another task it chooses next task as task with maximum priority. It describes common problem. Maybe there is more simple approach

I have the following code snippet that basically scans through the list of task that needs to be executed and each task is then given to the executor for execution. The JobExecutor in turn creates another executor (for doing db stuff...reading and writing data to queue) and completes the task. JobExecutor returns a Future<Boolean> for the tasks submitted. When one of the task fails, I want to gracefully interrupt all the threads and shutdown the executor by catching all the exceptions. What changes do I need to do? public class DataMovingClass { private static final AtomicInteger uniqueId =

I have a long running process that listens to events and do some intense processing. Currently I use Executors.newFixedThreadPool(x) to throttle the number of jobs that runs concurrently, but depending of the time of the day, and other various factors, I would like to be able to dynamically increase or decrease the number of concurrent threads. If I decrease the number of concurrent threads, I want the current running jobs to finish nicely. Is there a Java library that let me control and dynamically increase or decrease the number of concurrent threads running in a Thread Pool ? (The class