1

We have a Java 8 application that fetches data from social media APIs constantly and we keep getting java.net.UnknownHostException <host> (ex: java.net.UnknownHostException: graph.facebook.com) eventually when accessing the URLs. That happens roughly in < 5% of the requests (which are around 50-100 per minute in total, segregated in different JVM instances).

Thing is, at first I thought we had a DNS or internet problem in our Azure server, so I set up a script in crontab that does nslookup in both Instagram and Facebook APIs every minute, and after a whole day, not a single error occurred.

We connect through HTTPS using something like:

String facebookURL = "https://graph.facebook.com/v2.1/%s?access_token=%s&fields=name,picture&metadata=1";
// ... we replace the tokens here
HttpsURLConnection facebookConnection = (HttpsURLConnection) new URL(facebookURL).openConnection();

Any ideas on why we are getting this behavior or any other tests I could try? Would there be any SSL/socket limits that could produce the (wrong) java.net.UnknownHostException, or is it something I have to live with? As far as I know this exception is very straight forward, and our server is extremely stable in general.

We run our app in jdk1.8.0_111, Ubuntu 16.10 64bit and OpenSSL 1.0.2g.

Thanks :)

Michael
  • 41,989
  • 11
  • 82
  • 128
vitorrrr
  • 70
  • 7
  • Don't worry about including update messages in your questions or answers. Just make it as clean and concise as possible. I've edited it for you this time. I'll delete my comments now because your question has been updated. You can do the same :) – Michael Jul 14 '17 at 15:02

0 Answers0