Networking Section Index | Page 7

What is a resource leak?

Garbage collection manages only memory, not other system resources. If your Java program has plenty of free memory, garbage collection will not be triggered automatically. Usually, however, there...more

How can I find the size of a remote HTML document?

You can use the getContentLength() method of URLConnection. The example below shows you how. Be aware that this will only work if the server accurately reports the length of the file as part of ...more

How do I set the referer for a URLConnection?

Use the setRequestProperty() method of URLConnection. The following example shows how to do this properly: import java.net.*; import java.io.*; public class RequestProperty { public static ...more

How can I get URLConnection to bypass the proxy for certain addresses?

When using Sun's implementation of URL, URLConnection, or HttpURLConnection, to access an HTTP URL, you can set the system property http.nonProxyHosts to be a '|' separated list of hosts not to pr...more

Does a URLConnection using the FTP protocol support that protocol's RESTART command? If so, how can I initiate a restart?

As of the JDK 1.3, the included FTP protocol does not support the RESTART command.

How would you send a file over a socket connection?

If both ends of the connection knew exactly what was happening or expected (e.g. a single file with a constant filename, in the simplest case), you could do something as simple as have one end re...more

What is the best way to launch the default e-mail editor from a Java Application. Can a new message be automatically sent to the editor?

There is no standard way to launch the default e-mail editor from a Java Application. If you were in a Java Applet, you could leverage the showDocument() method of AppletContext and pass it a ma...more

Can I cast the return object from URL.openConnection() to an HttpURLConnection in an applet?

Unfortunately, you can't. Both IE and NN version 4 and below return objects whose type is not HttpURLConnection or a subclass thereof. Strictly speaking openConnection() is only guaranteed to r...more

What is the default space name used for a JavaSpace, and how do I change this default?

Sun's implementation of JavaSpaces, called "Outrigger", uses the default space name "JavaSpace". This can be changed by setting the Sun-specific system property com.sun.jini....more

Where is the source code for all the examples in the <JINI_ROOT>/example directory of the Jini distribution?

All the Jini examples are part of the com.sun.jini.example package. Although you might expect the source to be in the example directory, as is the common practice for other Java API distributions,...more

Is HTTP proxy supported when using java.net.Socket instead of URLConnection? I need to use Socket so I can use setSoTimeout() for non-blocking reads. When I switched from URLConnection to Socket, the proxyHost and proxyPort system properties had no effect.

HTTP proxies perform a function specific to the HTTP protocol. The HTTP protocol is implemented in whole by the class HttpURLConnection - it is in this implementation that the system properties r...more