I am trying to write a multithreaded program that runs two threads. The two threads execute a for loop together and print out numbers 0 to 99. The problem I am having is each thread runs the for loop 0 to 99, so I get 0 to 99 twice instead of them working together to get to 99.
My results look like this
1 1 2 2 3 3
I want something like this, where each thread prints a number all the way to 100.
1 2 3 4 all the way to 100 then stop
What am I doing wrong?
This is my code
public class JavaApplication220 implements Runnable {
public int i;
public void run() {
synchronized (this) {
for (i = 0; i < 100; i++) {
System.out.println(i);
try {
Thread.sleep(1);
} catch (InterruptedException ex) {
Logger.getLogger(JavaApplication220.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
}
}
This is the main() class
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class NewClass {
public static void main(String[] args) {
JavaApplication220 thread1 = new JavaApplication220();
JavaApplication220 thread2 = new JavaApplication220();
ExecutorService executor = Executors.newCachedThreadPool();
executor.execute(thread1);
executor.execute(thread2);
executor.shutdown();
}
}
Answer
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.atomic.AtomicInteger;
public class Test {
public static void main(String args[]){
AtomicInteger i = new AtomicInteger(0);
i.set(0);
TestingT thread1 = new TestingT(i);
TestingT thread2 = new TestingT(i);
ExecutorService executor = Executors.newCachedThreadPool();
executor.execute( thread1 );
executor.execute( thread2 );
executor.shutdown();
}
}
class TestingT implements Runnable {
AtomicInteger i;
TestingT(AtomicInteger i ){
this.i = i;
}
@Override
public void run(){
while(this.i.get() < 100) {
int i = this.i.incrementAndGet();
System.out.println(Thread.currentThread().getName()+" "+i);
}
}
}
this should works fine with your requirements