Report: ConcurrentModificationException when use AckWithTimout...

[duan-nguyen]

Describe the bug
Report: ConcurrentModificationException when use AckWithTimout...
(no issues with regular Ack(), only with AckWithTimout because of concurrent / thread-safe ...)

To Reproduce

Please fill the following code example:

Client

multi-thread...
        socket.emit("echo", null, new AckWithTimeout(3000) {
			@Override
			public void onSuccess(Object... args) {
				log.info(args[0].toString());	
			}
			@Override
			public void onTimeout() {
				log.warn("WARN: timout occured...");
			}
		});

Platform:

• MacOS or any...

Error
java.util.ConcurrentModificationException
at java.util.LinkedList$ListItr.checkForComodification(LinkedList.java:966)
at java.util.LinkedList$ListItr.next(LinkedList.java:888)
at io.socket.client.Socket$6$1.run(Socket.java:232)
at java.util.TimerThread.mainLoop(Timer.java:555)
at java.util.TimerThread.run(Timer.java:505)

Fix needed
Need to rewrite Socket.class to support thread-safe????
while (iterator.hasNext()) {
if (iterator.next().id == ackId) { <=== 232
iterator.remove();
}
}

[Harshvardhan5488]

I am Working on an Android Project in Kotlin that uses this library for socket.
I am facing the same issue. Is there any fix for it?
This crash appears a lot many times on the Prod.

Please provide any fix or update in the library.
Thanks

Here is the stack trace: (io.socket.client.Socket$6$1.run (Socket.java:232))
Fatal Exception: java.util.ConcurrentModificationException:
at java.util.LinkedList$ListItr.checkForComodification(LinkedList.java:970)
at java.util.LinkedList$ListItr.next(LinkedList.java:892)
at io.socket.client.Socket$6$1.run(Socket.java:232)
at java.util.TimerThread.mainLoop(Timer.java:563)
at java.util.TimerThread.run(Timer.java:513)

[darrachequesne]

This should be fixed by b00ae8e, included in version 2.1.1.

Please reopen if needed.

[seven4pl]

@darrachequesne hi, I have a very similar case with io.socket.client.Socket.clearAcks, when sending about 50 ACK's with timeout: 4 diffrent devices, Android 13 (SDK 33) and Android 14 (SDK 34), newest socket.io-client-java (version 2.1.1)

java.util.ConcurrentModificationException

Exception java.util.ConcurrentModificationException:
  at java.util.HashMap$HashIterator.nextNode (HashMap.java:1603)
  at java.util.HashMap$ValueIterator.next (HashMap.java:1631)
  at io.socket.client.Socket.clearAcks (Socket.java:294)
  at io.socket.client.Socket.onclose (Socket.java:286)
  at io.socket.client.Socket.access$400 (Socket.java:19)
  at io.socket.client.Socket$2$4.call (Socket.java:106)
  at io.socket.emitter.Emitter.emit (Emitter.java:117)
  at io.socket.client.Manager.onclose (Manager.java:472)
  at io.socket.client.Manager.access$1100 (Manager.java:22)
  at io.socket.client.Manager$4.call (Manager.java:349)
  at io.socket.emitter.Emitter.emit (Emitter.java:117)
  at io.socket.engineio.client.Socket.onClose (Socket.java:822)
  at io.socket.engineio.client.Socket.onError (Socket.java:784)
  at io.socket.engineio.client.Socket.access$900 (Socket.java:29)
  at io.socket.engineio.client.Socket$4.call (Socket.java:340)
  at io.socket.emitter.Emitter.emit (Emitter.java:117)
  at io.socket.engineio.client.Transport.onError (Transport.java:66)
  at io.socket.engineio.client.transports.WebSocket.access$400 (WebSocket.java:22)
  at io.socket.engineio.client.transports.WebSocket$1$5.run (WebSocket.java:107)
  at io.socket.thread.EventThread$2.run (EventThread.java:80)
  at java.util.concurrent.ThreadPoolExecutor.runWorker (ThreadPoolExecutor.java:1145)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run (ThreadPoolExecutor.java:644)
  at java.lang.Thread.run (Thread.java:1012)