Thread Control in Java

Question

I have a multi thread Java system that uses the class ThreadGroup which is deprecated.

With my current implementation I can’t "kill" a thread in lock either. How to implement efficient code for Thread in Java?

I need to have at least control over the execution time, startup and completion of my Pool threaded.

Simplified code of what I need to do more efficiently:

int threadAtivas = 5;
ThreadGroup threadGroup = new ThreadGroup("threads");
while(true){
    if(verificaQtdThreadsAtivas(threadGroup)){
        criaNovaThread(threadGroup);
    }else{
        Thread.sleep(1000);
    }
}

Answer 1

Use the ExecutorService, it’s a class for threads pool. You instantiate how many threads will run simultaneously, then add your Runnable in it and hopes to end.

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class SimpleThreadPool {

    public static void main(String[] args) {
        ExecutorService executor = Executors.newFixedThreadPool(5);
        for (int i = 0; i < 10; i++) {
            Runnable worker = new WorkerThread("" + i);
            executor.execute(worker);
          }
        executor.shutdown();
        while (!executor.isTerminated()) {
          // fica aqui enquanto está rodando as threads
        }
        System.out.println("Finished all threads");
    }

}