The Java environment is highly regarded in part because of its
suitability to writing programs that use and interact with the
resources on the Internet and the World Wide Web. In fact,
Java-capable browsers use this capability of the Java environment
to the extreme to transport and run applets over the net.
The Custom Networking and Security trail walks you through the
complexities of writing Internet-aware Java applications and
applets.
What You May Already Know About Networking in Java
This lesson describes the networking capabilities of the Java
environment that you may already be using without realizing it!
Working with URLs
A Uniform Resource Locator (URL) is an address of a resource on
the Internet. Your Java programs can use URLs to connect to
and retrieve information over the network. This lesson
provides a more complete definition of URL, shows you how to
create and parse URLs, how to open a connection to a URL,
and how to read from and write to those connections. In addition,
this lesson has a section for advanced networking programmers
who want to create their own URL content and stream handlers,
and a section describing two helper classes--InetAddress and URLEncoder.
All about Sockets
A socket is one end of a two-way communication link between
two programs running on the network. This lesson first shows you
how to read from and write to a socket from a client program communciating
with a standard server program--the echo server.
Also, this lesson walks you through the details of a complete
client/server example showing you how to implement both the client
and the server side of a client/server pair.
All about Datagrams
The previous lessons focused on "perfect" communication links between
applications running on the network. Perfect communication links guarantee
the arrival of all packets in the order they were sent. While necessary
for some applications, perfect links are overkill for others. These
applications use datagrams instead. The delivery of datagrams is not
guaranteed nor is the order in which they are delivered. This lesson
takes you step-by-step through a client/server example that uses
datagrams to communicate.
Providing Your Own Security Manager
One concern about running programs over the network becomes security.
Java lets you implement your own security protocols using a custom
security manager.
