[Bug classpath/70661] New: URLConnection throws incorrect exception if address cannot be resolved

[guillerodriguez.dev at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70661

            Bug ID: 70661
           Summary: URLConnection throws incorrect exception if address
                    cannot be resolved
           Product: classpath
           Version: 0.99
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: classpath
          Assignee: unassigned at gcc dot gnu.org
          Reporter: guillerodriguez.dev at gmail dot com
  Target Milestone: ---

According to the API specification, the URLConnection.connect() method should
throw an IOException if an error occurs. However in GNU Classpath if the
address can be resolved, an java.nio.channels.UnresolvedAddressException is
thrown instead. UnresolvedAddressException is a subclass of
IllegalArgumentException, not IOException, so this breaks the API contract.

Here is a sample test case:

===
import java.net.URL;
import java.net.URLConnection;

public class UnresolvedAddress
{
        public static void main(String args[]) throws Exception
        {
                URL url = new URL("http", "someinvalidsitename.com", 80,
"index.html");
                URLConnection connection = url.openConnection();
                connection.setUseCaches(false);
                connection.connect();
        }
}
===

This results in the following:

===
Exception in thread "main" java.nio.channels.UnresolvedAddressException
   at gnu.java.nio.SocketChannelImpl.connect(SocketChannelImpl.java:160)
   at gnu.java.net.PlainSocketImpl.connect(PlainSocketImpl.java:281)
   at java.net.Socket.connect(Socket.java:463)
   at java.net.Socket.connect(Socket.java:414)
   at
gnu.java.net.protocol.http.HTTPConnection.getSocket(HTTPConnection.java:721)
   at
gnu.java.net.protocol.http.HTTPConnection.getOutputStream(HTTPConnection.java:802)
   at gnu.java.net.protocol.http.Request.dispatch(Request.java:292)
   at
gnu.java.net.protocol.http.HTTPURLConnection.connect(HTTPURLConnection.java:219)
   at UnresolvedAddress.main(UnresolvedAddress.java:11)
===

Note that the JDK does the right thing here:

===
Exception in thread "main" java.net.UnknownHostException:
someinvalidsitename.com
        at
java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:175)
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:385)
        at java.net.Socket.connect(Socket.java:546)
        at java.net.Socket.connect(Socket.java:495)
        at sun.net.NetworkClient.doConnect(NetworkClient.java:178)
        at sun.net.www.http.HttpClient.openServer(HttpClient.java:427)
        at sun.net.www.http.HttpClient.openServer(HttpClient.java:529)
        at sun.net.www.http.HttpClient.<init>(HttpClient.java:213)
        at sun.net.www.http.HttpClient.New(HttpClient.java:306)
        at sun.net.www.http.HttpClient.New(HttpClient.java:325)
        at
sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:955)
        at
sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:891)
        at
sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:809)
        at UnresolvedAddress.main(UnresolvedAddress.java:11)
===