Java.Net.Connectexception :Connection Timed Out: Connect

java.net.ConnectException :connection timed out: connect?

The error message says it all: your connection timed out. This means your request did not get a response within some (default) timeframe. The reasons that no response was received is likely to be one of:

a) The IP/domain or port is incorrect
b) The IP/domain or port (i.e service) is down
c) The IP/domain is taking longer than your default timeout to respond
d) You have a firewall that is blocking requests or responses on whatever port you are using
e) You have a firewall that is blocking requests to that particular host
f) Your internet access is down

Note that firewalls and port or IP blocking may be in place by your ISP

Getting connection timeout to URL, which I'm otherwise able to connect via browser in the same system

Sorry, it was my mistake. If anyone is seeing this:

The problem came from how I used proxy. If you are NOT able to connect to a website which is otherwise accessible via browser in same system, then you need a proxy in your java code.

For example:

Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress("google.com", 80));

Hope this helps. If you have any doubts regarding this, I'll be happy to help.

Note: Don't use "https" for proxy. Give only domain name.

I/O timeout exception (java.net.ConnectException) When calling API

I/O exception is occur when there is an issue in reading from the url, can you able to get the stack stacktrace, will give an insight about the issue, it could be the server unavailable or not found anything from http 400+

so please add this to your catch block and will help you get an idea, what went wrong.

catch(Exception e)
{
   e.printStacktrace();
}

java.net.ConnectException: Connection refused timeout

There is no such thing as a "connection refused timeout".

"Connection refused" happens when the server sees the connection request, but there is no service listening for connections on the IP + port that the request is directed to. The server then "refuses" the connection. This typically happens instantly, so so no timeout is triggered.

"Connection timed out" happens (typically) when something stops the connection request from reaching the server^{1, 2}. So the client-side will wait for the response from the server, and then resend / wait a few times. And eventually the time allotted for establishing a connection will expire ... and the connection times out.

As you can see these are different scenarios. And they are reported back to the Java client-side differently.

So the reason you are not getting timeouts is that the "connection refused" responses are coming back quick enough that your configured timeout is not exceeded.

That might also explain why setting the connect timeout small might have changed the behavior. There may also be issues with the granularity of the timeout that the OS allows Java to set.

To investigate this further, I think we would need a minimal reproducible example. For example, we need to see how you have implemented the code that manages the server-socket and accepts connections on the server side.

^{1 - The blockage could be on the server's reply packets.}
^{2 - There are various possible causes for this kind of thing. The most likely are a firewall blocking traffic somewhere, a network routing problem, or using a private IP address on the wrong network.}

Java.Net.Connectexception :Connection Timed Out: Connect