Slower When threaded.

[john sayeau]

I also posted this in the beginner section as I am one.
I have two simple programs that do the same thing. One threaded one not. I'm doing something wrong in the threaded one as it takes , on average , 4 times longer to do the same ting as the unthreaded version. I'm running two threads on a macbook pro. The activiy monitor show both cores going really hard(95%). Can someone point me in the right direction?
Here is the threaded version.
Main:

 
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.logging.Level;
import java.util.logging.Logger;

public class Main {

    public static void main(String[] args) {
        ExecutorService exec = Executors.newFixedThreadPool(2);
        for(int i = 0; i < 2; i++){
            exec.execute(new NumberGenerator());
        }
        exec.shutdown();
    }
}

NumberGenerator:

    
package randomnumbersthreaded;

public class NumberGenerator implements Runnable {
    public static int numberOfMatches = 0;

    public void run() {
        while(true){
            if(numberOfMatches == 6){
                 break;
             }
            int a = (int)(Math.random() * 49) +1;
            int b = (int)(Math.random() * 49) +1;
            int c = (int)(Math.random() * 49) +1;
            int d = (int)(Math.random() * 49) +1;
            int e = (int)(Math.random() * 49) +1;
             int f = (int)(Math.random() * 49) +1;
            if(( a == b) && ( a== c)&& (a == d) && ( a == e) && ( a ==f)){
               System.out.println(" a Match! " +a );
               numberOfMatches++;
            }
        }  
    }

}

here is the unthreaded version:

    
package randomnumbers;

public class Main {

    public static void main(String[] args) {
        long startTime = System.currentTimeMillis();
        int totalNums = 0;
        while(true){
            int a = (int)(Math.random() * 49) +1;
            int b = (int)(Math.random() * 49) +1;
            int c = (int)(Math.random() * 49) +1;
            int d = (int)(Math.random() * 49) +1;
            int e = (int)(Math.random() * 49) +1;
            int f = (int)(Math.random() * 49) +1;
            if(( a == b) && ( a== c)&& (a == d) && ( a == e) && ( a ==f)){
                System.out.println(" a Match! " +a );
                totalNums++;
            }
            if(totalNums == 6)
                break;

        }
        long finishTime = System.currentTimeMillis();
        long minutes = ((finishTime - startTime)/1000)/60;
        long seconds = ((finishTime - startTime)/1000)%60;
        System.out.println("run time = " + minutes + ":" + seconds);
    }

}

[Paul Clapham]

It looks like you cross-posted this over here: http://www.coderanch.com/t/513688/java/java/Threading.

Please CarefullyChooseOneForum for your posts. I will lock this one.