URLConnection.getInputStream and synchronization.

Question

I can't quite understand why url.getInputStream must by globaly synchronized, if it isn't I will start to receive "connection refused" exceptions
import java.net.*;
import java.io.*;
public class TestURL {
    private final Object lock = new Object();
    public void test() {
        for(int i=0;i<1000;i++) {
            new Thread(new Runnable() {
                public void run() {
                    try {
                        while(true) {
                           URLConnection url = null;
                           url = new URL("http://localhost:5222").openConnection();
                           InputStream s;
                           synchronized(TestURL.this.lock) {
                               s = url.getInputStream();
                           while(s.read() != -1) {};                            
                           s.close();
                           System.out.println(Thread.currentThread().hashCode());
                    }catch(Exception e) {
                        e.printStackTrace();
            }).start();
            System.out.println(i);
        while(true);
}

Answer 1

moonlighting wrote:
Hmmm, I don't quite understand your answer could you be more specific ?Without the synchronization you create and start 1000 threads with each one accessing the same URL. Can the server cope with 1000 requests at pretty much the same time?
With the synchronization, each thread has to acquire a lock on the object referenced by 'TestURL.this.lock' so only one can run at a time. All the other 999 will be suspended until they can acquire the lock.