How to detect the server disconnection to the client immediately in Java(Android) socket communication

Question

I am working on socket programming. Is there any way to detect the server disconnection to the client immediately.

I used socket.isConnected , isBound methods but I did't get good results.

I tried to read the data from the stream continuously to check but it blocks that if data is not available or return from the server and I don't want to write garbage data to send each time to check the connection with the server.

Please suggest any suggestions.

Answer 1

It depends on which socket type you're using. Even then it is unavoidable to implement a keep-alive mechanism for your specific purpose.

The default TCP keep-alive mechanism checks every 2 hours (!) if the connection still exists. This default value can be changed but it may not work. See:

Does a TCP socket connection have a "keep alive"?

UDP on the other hand is stateless; there is no connection. The context in which socket.isConnected() should be interpreted is whether it's bound to a local port.

For UDP it is an absolute requirement to send ping/pongs back and forth to determine connectivity.

Hope it helps.