Common Exceptions

Many exceptions should be self explanatory. However here are some common exceptions that can be thrown by HTTPClient (they're all subclasses of java.io.IOException) and for which the true cause might not be obvious.

java.net.SocketException: Connection refused

(connecting to the local host) The server is not running (nobody is listening on the specified port).

java.net.SocketException: Invalid argument

(connecting to a different host) The server is not running (nobody is listening on the specified port).

(connecting to a different host) The host is not reachable.

java.net.UnknownHostException: host

The host name host could not be translated to an IP-address.

java.net.SocketException: Malformed reply from SOCKS server

The SOCKS server refused the connection.

The SOCKS server is running version 5; the JDK currently only supports version 4.

Also note the following under JDK 1.0.2: If you try to create a new connection, giving an IP-address instead of a host name (e.g. new HTTPConnection("12.34.32.127")) and this fails with an IOException, then it might be due to the problem described in http://java.sun.com/products/jdk/1.0.2/KnownBugs.html#Net. A fix is available at http://www.cdt.luth.se/~peppar/java/InetAddress/.

If you have any further exceptions that you think should be listed here, please let me know.