CODEWITHSUNDEEP
javamultithreading
blue-sky
blue-sky

Reputation: 53806

Why is var not incremented in this example?

In below code I'm attempting to count the number of times the execute method is invoked but count is not incremented : 

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import org.junit.Test;

public class ThreadTest {

    @Test
    public void testThread() {

        ExecutorService es = Executors.newCachedThreadPool();
        for (int counter = 0; counter < 10; ++counter) {

            int count = 0;
            for (int i = 0; i < 4; i++) {
                es.execute(new FooWorker());
            }

            count = count + 1;
            System.out.println((count * 4) + "," + count + " threads created");

        }

    }

    private final class FooWorker implements Runnable {
        public void run() {
            System.out.println("in run");
        }
    }

}

Why is count not incremented ?

Upvotes: 0

Views: 79

Answers (2)

brso05
brso05

Reputation: 13222

You are resetting count to 0 each iteration...

    for (int counter = 0; counter < 10; ++counter) {

        int count = 0; // count is reset to 0 every loop
        for (int i = 0; i < 4; i++) {
            es.execute(new FooWorker());
        }

        count = count + 1; // count will always be 1 here
        System.out.println((count * 4) + "," + count + " threads created");

    }

Upvotes: 4

peter.petrov
peter.petrov

Reputation: 39457

You're resetting count each time in the outer loop. I am not sure if that's intended.

Upvotes: 0

Related Questions