Multiple socket io client connections in java

Question

I have to implement client functionality using https://github.com/socketio/socket.io-client-java. I have socket.io nodejs server 4.x version. I want to establish around 300-700 socket connections using threadpool ThreadPoolExecutor in a loop after some fixed delay. I have tried to implement this, the socket connections to server established but after sometimes got disconnected.Please help me figure the root cause of the issue of disconnections. I have tired

• Without using threads at all.

• Using singleThreadPool

• Using fixedThreadPool

• Using scheduledThreadPool

   ScheduledThreadPoolExecutor executor = (ScheduledThreadPoolExecutor) Executors.newScheduledThreadPool(200);
   ScheduledFuture<?> future;
   future= executor.scheduleAtFixedRate(() -> {
   for(int i=1;i<=300;i++) {
  
           IO.Options options = IO.Options.builder()
                   .setPath("/agent-manager/socket.io")
                   .setTransports(new String[]{Polling.NAME,WebSocket.NAME})
                   .setAuth(token)
                   .build();
  
            socket = IO.socket(URI.create("wss://localhost:3000"), options);
            socket.on("connect_error", new Emitter.Listener() {
               @Override
               public void call(Object... args) {
                   System.out.println(args[0]);
               }
           }).on("connect", new Emitter.Listener() {
               @Override
               public void call(Object... args) {
                   System.out.println(socket.id() +" "+i+" connected");
               }
           }).on("disconnect", new Emitter.Listener() {
               @Override
               public void call(Object... args) {
                   System.out.println(socket.id() +" "+i+" disconnected");
               }
           });
           socket.connect();
           lock.countDown();
       }
       }, 1000, delay, TimeUnit.MILLISECONDS);
       lock.await(delay, TimeUnit.MILLISECONDS);
       future.cancel(true);
  

In all above cases, disconnections appear after few seconds. Is there some sort of socket object ttl expiration, connection timeout, or server & client are not sending any data in some time, so due to inactivity the disconnections appears? How to keep connections sustained?