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I am trying to data from a server. Sometimes my code fails due to an UnknownHostException. Why is that? What is the cause of this problem?

This may occur if a hiccup in DNS server has occurred. Apart from making the DNS server more robust or looking for another one, you can also just use the full IP address instead of the hostname. This way it doesn't need to lookup the IP address based on the hostname. However, I would rather fix the DNS issue and prefer the DNS since IP addresses may change from time to time.

Why doses this code sometimes throw UnknownHostException but , Networking code sometimes throws UnknownHostException (4 answers) Just a guess - is it possible that sometimes your app can not connect to the a SocketTimeoutException instead of an UnknownHostException - your� InetAddress.getLocalHost() throws UnknownHostException (9 answers) Networking code sometimes throws UnknownHostException (4 answers) Closed 2 months ago .

An UnknownHostException indicates the host specified couldn't be translated to an IP address. It could very well be a problem with your DNS server.

Networking code sometimes throws UnknownHostException, 问题I am trying to data from a server. Sometimes my code fails due to an UnknownHostException. Why is that? What is the cause of this problem? Next up in our comprehensive Java Exception Handling series we’ll be looking over the UnknownHostException.The UnknownHostException can be thrown in a variety of scenarios in which a remote connection fails due to an invalid or unknown host (i.e. IP, URL, URI, etc).

If the DNS resolution fails intermittently, catch the exception and try again until you get name resolution. You can only control, what you can control... And if you can't control/fix the DNS server, make your app robust enough to handle the quirky DNS server., UnknownHostException – How to solve UnknownHostException Socket (or any other method that throws an UnknownHostException ), and� A single network interface may be bound to more than one IP address. This situation isn’t common these days, but it does happen. The getInetAddresses() method returns a java.util.Enumeration containing an InetAddress object for each IP address the interface is bound to. For example, this code fragment lists all the IP addresses for the eth0

I too am seeing sporadic UnknownHostExceptions in Java for no apparent reason. The solution is just to retry a few times. Here is a wrapper for DocumentBuilder.parse that does this:

static Document DocumentBuilder_parse(DocumentBuilder b, String uri) throws SAXException, IOException {
  UnknownHostException lastException = null;
  for (int tries = 0; tries < 2; tries++) {
    try {
      return b.parse(uri);
    } catch (UnknownHostException e) {
      lastException = e;
      System.out.println("Retrying because of: " + e);
  throw lastException;

Android UnknownHostException Facebook SDK, , IP- , . ( , API , HttpUrlConnection DefaultHttpClient), , , , Android, DNS TTL: 7904: Android TTL DNS 10. Android 4.1, . Networking code sometimes throws UnknownHostException. networking is not my strong suit so I apologize if my questions sounds dumb to those of you with the knows in native-image mode, not in JVM , When playing with Quarkus I noticed UnknownHostException in to host and review code, manage projects, and build software together. But sometimes users don't have rights to edit /etc/hosts or they don't know they can do it. static void main(String[] args) throws UnknownHostException { InetAddress� The following are top voted examples for showing how to use examples are extracted from open source projects. You can vote up the examples you like and your votes will be used in our system to generate more good examples.

Java Code Examples, This page provides Java code examples for public List<InetAddress> lookup(String hostname) throws UnknownHostException { if and will often return the * loopback address, which is not valid for network� Sometimes the ES Docker Container hasn't yet started, when my main container (the one that runs my code and connects to ES) starts. Then InetAddress.getByName("search") below throws a (because Docker's DNS server hasn't yet assigned an IP address to the search container, as far as I've understood).

InetAddress (Java Platform SE 8 ), This address is often used when testing a client. a combination of local machine configuration information and network naming services such to see if the calling code is allowed to know the hostname for this IP address, i.e., to connect to the host. public static InetAddress getLocalHost() throws UnknownHostException. Returns an <code>InetAddress</code> object encapsulating what is most likely the machine's LAN IP address. <p/> This method is intended for use as a replacement of JDK method <code>InetAddress.getLocalHost</code>, because; that method is ambiguous on Linux systems. Linux systems enumerate the loopback network interface the same

  • An UnknownHostException is thrown if a occurs while creating a connection to the remote host for a remote method call. Something isn't resolving at the DNS level this isn't a java or an xml problem.
  • Thanks BalusC :). Great, you gave the ip. Now the DNS itself doesn't come into picture. But it's not working. Now i get this error :-
  • Even when i type "" i get nothing. Is this ip correct? When i did ping i got this ip However in this also i get the same exception in java and in browser also nothing displays.
  • Ok MarkPeters, so how should i resolve this? since i have to submit my work in college and i don't think i will able to have access to college's router and change the dns server in it :(
  • @Nitesh: Is it failing in the college's environment or only in your local environment? If it's inconsistently failing from the college's environment, I would both notify your teacher or tutor that there may be an environment problem that's out of your control, and also try to lobby your college IT staff to diagnose and fix the problem. You might consider an approach where you catch the exception and try again a few times, perhaps a few seconds/minutes apart.
  • //Override system DNS setting with Google free DNS server System.setProperty("", ""); System.setProperty("", "dns,sun");