RFE 4523221 Default Connection Timeout in Java Plug-in Networking support was
added in hopper so this needs to be documented in the plugin doc.

When a connection is made by the applet and the server doesn't respond properly,
the applet may appear to hang and may also cause the browser to hang because
the network connection timeout is none by default.

The Java Plug-in has added a default network timeout value (2 minutes) for all
HTTP connections to avoid this problem. The user can override this setting
by specifying in the Java Plug-in Control Panel (Advanced tab) Java Runtime
Parameters.
-Dsun.net.client.defaultConnectTimeout=<value in milliseconds>

Another networking property that a user can set is sun.net.client.defaultReadTimeout.
Note: This one is not set by the Java Plug-in.

Networking Properties

sun.net.client.defaultConnectTimeout (default: -1)
sun.net.client.defaultReadTimeout (default: -1)

These properties specify the default connect and read timeout for the protocol
handler used by java.net.URLConnection.

sun.net.client.defaultConnectTimeout specifies the timeout (in milliseconds) to
establish the connection to the host. For example for http connections it is the
timeout when establishing the connection to the http server. For ftp connection
it is the timeout when establishing the connection to ftp servers.

sun.net.client.defaultReadTimeout specifies the timeout (in milliseconds) when
reading from input stream when a connection is established to a resource.