Decreasing max-threads on a unbounded queuesless executor generates IllegalArgumentException -------------------------------------------------------------------------------------------- Key: WFLY-2336 URL: https://issues.jboss.org/browse/WFLY-2336 Project: WildFly Issue Type: Bug Affects Versions: 8.0.0.Beta1 Reporter: Aaron Ogburn Priority: Minor Create an unbounded queueless executor <unbounded-queue-thread-pool name="uq-thread-pool"> <max-threads count="350"/> <keepalive-time time="5" unit="minutes"/> </unbounded-queue-thread-pool> Modifying max-threads fails: /subsystem=threads/unbounded-queue-thread-pool=uq-thread-pool:write-attribute(name=max-threads,value=300) { "outcome" => "failed", "failure-description" => "JBAS014749: Operation handler failed: null", "rolled-back" => true } ERROR [org.jboss.as.controller.management-operation] (management-handler-thread - 1) JBAS014612: Operation ("write-attribute") failed - address: ([ ("subsystem" => "threads"), ("unbounded-queue-thread-pool" => "uq-thread-pool") ]): java.lang.IllegalArgumentException at java.util.concurrent.ThreadPoolExecutor.setMaximumPoolSize(ThreadPoolExecutor.java:1620) [rt.jar:1.7.0] at org.jboss.threads.JBossThreadPoolExecutor.setMaxThreads(JBossThreadPoolExecutor.java:95) [jboss-threads-2.1.1.Final.jar:2.1.1.Final] at org.jboss.as.threads.ManagedJBossThreadPoolExecutorService.setMaxThreads(ManagedJBossThreadPoolExecutorService.java:86) at org.jboss.as.threads.UnboundedQueueThreadPoolService.setMaxThreads(UnboundedQueueThreadPoolService.java:91) The core pool size needs to be adjusted in line with the max pool size and in the right order to avoid that since max threads can't be less than core threads.