java.net.SocketException: Software caused connection abort: recv failed [duplicate]

Question

I haven't been able to find an adequate answer to what exactly the following error means:

java.net.SocketException: Software caused connection abort: recv failed

Notes:

• This error is infrequent and unpredictable; although getting this error means that all future requests for URIs will also fail.
• The only solution that works (also, only occasionally) is to reboot Tomcat and/or the actual machine (Windows in this case).
• The URI is definitely available (as confirmed by asking the browser to do the fetch).

Relevant code:

BufferedReader reader;
try { 
 URL url = new URL(URI);
 reader = new BufferedReader(new InputStreamReader(url.openStream())));
} catch( MalformedURLException e ) { 
 throw new IOException("Expecting a well-formed URL: " + e); 
}//end try: Have a stream

String buffer;
StringBuilder result = new StringBuilder();
while( null != (buffer = reader.readLine()) ) { 
 result.append(buffer); 
}//end while: Got the contents.
reader.close();

Answer 1

This also happens if your TLS client is unable to be authenticate by the server configured to require client authentication.

Answer 2

This usually means that there was a network error, such as a TCP timeout. I would start by placing a sniffer (wireshark) on the connection to see if you can see any problems. If there is a TCP error, you should be able to see it. Also, you can check your router logs, if this is applicable. If wireless is involved anywhere, that is another source for these kind of errors.

Answer 3

This error occurs when a connection is closed abruptly (when a TCP connection is reset while there is still data in the send buffer). The condition is very similar to a much more common 'Connection reset by peer'. It can happen sporadically when connecting over the Internet, but also systematically if the timing is right (e.g. with keep-alive connections on localhost).

An HTTP client should just re-open the connection and retry the request. It is important to understand that when a connection is in this state, there is no way out of it other than to close it. Any attempt to send or receive will produce the same error.

Don't use URL.open(), use Apache-Commons HttpClient which has a retry mechanism, connection pooling, keep-alive and many other features.

Sample usage:

HttpClient httpClient = HttpClients.custom()
            .setConnectionTimeToLive(20, TimeUnit.SECONDS)
            .setMaxConnTotal(400).setMaxConnPerRoute(400)
            .setDefaultRequestConfig(RequestConfig.custom()
                    .setSocketTimeout(30000).setConnectTimeout(5000).build())
            .setRetryHandler(new DefaultHttpRequestRetryHandler(5, true))
            .build();
// the httpClient should be re-used because it is pooled and thread-safe.

HttpGet request = new HttpGet(uri);
HttpResponse response = httpClient.execute(request);
reader = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
// handle response ...