I am confused -- Will this code always work?
- by Shekhar
Hello,
I have written this piece of code
public class Test{
public static void main(String[] args) {
List<Integer> list = new ArrayList<Integer>();
for(int i = 1;i<= 4;i++){
new Thread(new TestTask(i, list)).start();
}
while(list.size() != 4){
// this while loop required so that all threads complete their work
}
System.out.println("List "+list);
}
}
class TestTask implements Runnable{
private int sequence;
private List<Integer> list;
public TestTask(int sequence, List<Integer> list) {
this.sequence = sequence;
this.list = list;
}
@Override
public void run() {
list.add(sequence);
}
}
This code works and prints all the four elements of list on my machine.
My question is that will this code always work. I think there might be a issue in this code
when two/or more threads add element to this list at the same point. In that case it while
loop will never end and code will fail.
Can anybody suggest a better way to do this? I am not very good at multithreading and don't
know which concurrent collection i can use?
Thanks
Shekhar
