java.net.SocketTimeoutException: Read timed out under Tomcat

Server is trying to read data from the request, but its taking longer than the timeout value for the data to arrive from the client. Timeout here would typically be tomcat connector -> connectionTimeout attribute.

Correct.

Client has a read timeout set, and server is taking longer than that to respond.

No. That would cause a timeout at the client.

One of the threads i went through, said this can happen with high concurrency and if the keepalive is enabled.

Could be in theory, trying to read the next request on a connection, but Tomcat wouldn't log it that way.

It just means the client isn't sending. You don't need to worry about it. Browser clients come and go in all sorts of strange ways.

Here are the basic instructions:-

1. Locate the "server.xml" file in the "conf" folder beneath Tomcat's base directory (i.e. %CATALINA_HOME%/conf/server.xml).
2. Open the file in an editor and search for <Connector.
3. Locate the relevant connector that is timing out - this will typically be the HTTP connector, i.e. the one with protocol="HTTP/1.1".
4. If a connectionTimeout value is set on the connector, it may need to be increased - e.g. from 20000 milliseconds (= 20 seconds) to 120000 milliseconds (= 2 minutes). If no connectionTimeout property value is set on the connector, the default is 60 seconds - if this is insufficient, the property may need to be added.
5. Restart Tomcat

Connection.Response resp = Jsoup.connect(url) //
                .timeout(20000) //
                .method(Connection.Method.GET) //
                .execute();

actually, the error occurs when you have slow internet so try to maximize the timeout time and then your code will definitely work as it works for me.

I had the same problem while trying to read the data from the request body. In my case which occurs randomly only to the mobile-based client devices. So I have increased the connectionUploadTimeout to 1min as suggested by this link

This happenned to my application, actually I was using a single Object which was being called by multiple functions and those were not thread safe.

Something like this :

Class A{
    Object B;
    function1(){
        B.doSomething();
    }
    function2(){
        B.doSomething();
    }
}

As they were not threadsafe, I was getting these errors :

redis.clients.jedis.exceptions.JedisConnectionException: java.net.SocketException: Socket is closed

and

redis.clients.jedis.exceptions.JedisConnectionException: java.net.SocketTimeoutException: Read timed out

This is how I fixed it :

Class A{
    function1(){
        Object B;
        B.doSomething();
    }
    function2(){    
        Object B;
        B.doSomething();
    }
}

Hope it helps