ThreadPoolExecutor is an object that efficiently manages and controls the execution of multiple tasks in a thread pool. A thread pool
is a collection of pre-initialized threads ready to execute tasks. Instead of creating a new thread for each task, which can be costly in terms of
system resources, a thread pool reuses existing threads.
java.util.concurrent.ScheduledThreadPoolExecutor is an extension of ThreadPoolExecutor that can additionally schedule
commands to run after a given delay or to execute periodically.
ScheduledThreadPoolExecutor 's pool is sized with corePoolSize, so setting corePoolSize to zero means the
executor will have no threads and run nothing. corePoolSize should have a value greater than zero and valid for your tasks.
This rule detects instances where corePoolSize is set to zero via its setter or the object constructor.
Noncompliant code example
public void do(){
int poolSize = 5; // value greater than 0
ScheduledThreadPoolExecutor threadPool1 = new ScheduledThreadPoolExecutor(0); // Noncompliant
ScheduledThreadPoolExecutor threadPool2 = new ScheduledThreadPoolExecutor(poolSize);
threadPool2.setCorePoolSize(0); // Noncompliant
}
